Ha! I knew The Last Mabelcorn will give you ideas.

Now, this is more a character study than anything else. This is also my view on why Ford is constantly keeping secrets.

Trust no one

As far as Ford remembered, before the portal he was never truly alone. For the first eighteen years of his life he was sharing his room, class and playtime with his twin brother, who was also his best friend. Sometimes it was troublesome, especially when Stanley wanted to play something while Stanford has just opened the book he was waiting to read whole day, but overall, he liked spending time with Stan. Other kids were making fun of Ford's additional fingers and nerdiness. Stan, on the other hand, always was ready to fight them and then console his brother.

But then the science project fiasco happened, Stan got disowned and kicked out of the house, and for the first time in his life Ford was alone. The room he shared with his twin was now horribly empty and awfully quiet. But he still had a company – a company of his thoughts, anger and the sinking feeling of betrayal. (Some part of him was also a bit worried about Stanley, but it wasn't heard over the boiling wrath.)

When he moved on to the university, he met Fiddleford McGucket, a man that later became his friend. Maybe not as close as Stanley, nevertheless, a friend. They were having classes together, they were studying together, they were even playing Dungeons, Dungeons and More Dungeons together. Their companionship was different than the brotherhood Ford shared with Stan. It was based on common interests and hunger for knowledge. They've spent hours talking about theories, science projects and books they were reading at the time. Ford had to admit – after so many years, it was nice to find someone, who understood him on scientific level.

However, Fiddleford wasn't interested in supernatural. Whenever Ford was bringing up UFO, ghosts, conspiracy theories, parapsychology or other things out of this world, his friend was either dismissing it or changing the subject. Sometimes he was even snapping at him, because Ford's talk about supernatural was giving him nightmares… or just annoying him.

Ford graduated three years ahead of schedule and got a grant. He and Fiddleford went their separate ways. Stanford went to Gravity Falls to study supernatural, but even there he wasn't completely alone. As much as he didn't like the nosiness of Gravity Falls townsfolk, he had to interact with them from time to time – to build the hut, to get groceries, to gather information about unusual situation that occurred lately. But still, there was nobody he actually considered a friend; nobody he was close with.

That is, until he met Bill. Bill came to him (well, technically Ford summoned him, nevertheless…), when Stanford Pines was frustrated and felt that his research have stuck. Oh, he was so tempting, so convincing. He knew what to say and what to offer to gain Ford's trust. He pulled just the right strings to make a lonely, desperate and self-centered scientist to do what Bill wanted him to do. He was flattering, he was entertaining, he was promising Ford greatness.

And so Ford fell into this demon's trap, called Fiddleford for help and built the portal that later was a cause of his downfall. He also was foolish enough to let him go into his mind. He realized too late that Bill Cipher couldn't be trusted. And even when Bill was supposed to be away, Ford couldn't shake the feeling of being observed by him. There was not even one moment in this whole period of time, when Ford would feel alone in his shack. That – alongside with the familiar feeling of betrayal and the realization that he fell for demon's sweet words – made him miserable, not to mention – paranoid.

Back then Ford wanted so badly to be left alone. Loneliness seemed to be better than this horrible sensation of Bill's eyes fallowing his every step. Loneliness seemed to be better than whispers in the dark. Ford was almost on the verge of insanity. And since Bill could enter minds, the scientist wrote in the journals these three fateful words.

Trust no one.

And then he was sucked into portal.

All the moments of loneliness that happened to him were nothing in comparison to thirty years of being completely on his own in a place where everything was foreign and everything could turn out to be dangerous. Thirty years of cautiously looking over his shoulder. Thirty years of keeping his thoughts and feelings for himself. Thirty years of not having a friend.

And there was always this thought on the back of his head; this conviction he had ever since his encounter with Bill.

Trust no one.

Even before the portal he learned that keeping secrets was the best policy. Besides, it wasn't like he had anybody he could deem trustworthy. Everybody he trusted – Fiddleford, Bill, even his own brother – turned out to leave and/or betray him one way or another. Seriously, he was better off without them. He didn't need anybody. He could take care of himself…

Only he was so horribly lonely at nights. He was longing for human company. For someone, who would talk to him, joke with him, console him in a moment of hopelessness. He wanted so badly to tell somebody how horribly he felt. But it couldn't be done. He knew it was impossible. He was going to spent rest of his days alone.

But then the portal was opened and when Ford went through it, he found four people waiting for him on the other side. His brother – who apparently spent all these years working on the portal to bring him back – informed him that twelve year old twins and a big guy with front teeth were his family. Suddenly, in one quick moment, Ford wasn't alone, anymore. There were people who wanted to spend time with him, even talk to him. After thirty years, he could fulfill his need for human company… But there were so many reasons against opening up to anybody.

One was, of course, this whole thing between him and Stanley. It was sad, but Stanford knew he couldn't open to his brother like in the old days. Partly because of Stan's faults in the past, partly because Ford was convinced that his twin will never understand him, and partly because he wasn't sure if Stan will even want to listen after all those years. No, if Ford was going to ever say anything to his brother, first they had to repair their relationship.

The next problem was the deal he and Stan made. Considering the situation, it was logical that Stanford would repair the damage, while Stanley would take care of the kids during the summer. However, when Ford told him to leave the shack when summer is over, Stan agreed on it, but under one condition – Ford had to stay away from kids. Stan even went so far that he warned twins about him.

My brother is a dangerous know-it-all and the stuff he's messing with is even worse. Do yourself a favor and stay away from him. You hear me?

It wasn't that Stanford didn't understand him. After all, Stanley only wanted to protect children. And to some degree he was probably right. What Ford was doing in the basement, wasn't safe and Dipper and Mabel shouldn't hang around it. Still, when Ford heard these words, it hurt. Because that meant that his own brother didn't trust him.

The third problem was the things Ford was dealing with. The horrors of the portal, plaguing him in the sleep, the dangers of said portal, the shame he felt… he wasn't sure if they would understand.

Finally there was this conviction he carried with himself all those years.

Trust no one.

He was used to not trusting. He was used to keeping secrets. He spent so long doing it that it became his second nature. Still, he felt the pang of sadness, being alone in the basement and knowing that his newfound family was above him.

But then came Dipper with a Dungeons, Dungeons and More Dungeons dice. And suddenly Ford had a friend again. It was a friend with whom he could talk about tabletop games and about weird things happening around them. Dipper was so much like Stanford – so curious and nerdy, Ford knew he found a soulmate. It was only the matter of time, when he will open to the kid. And so he did – showing him the Infinity Dice and then – telling him about the rift. Of all the people in the shack – hell, of all the people in the multiverse – he trusted Dipper the most.

But there was still things he just couldn't tell or show to the kid. It had a lot to do with the fact that Dipper liked him. No, not just "liked". He adored him. He said it himself – he spent whole summer wondering who was the mysterious Author of the journals and now the Author was here, in the Mystery Shack. Dipper probably already had some picture of him in mind; a picture painted by assumptions and dreams. Maybe the actual meeting with Ford and all these times when they were hanging out, changed this picture a bit, nevertheless, the admiration was still there.

Ford was flattered by it. He wanted to be seen as someone tough and strong, and smart. He wanted to be someone's hero. Especially when it was Dipper. That's why he couldn't bear the thought that this child would learn a not-so-pretty truth about his idol and stop to look up to him. But it was more than that. So, so much more. Ford was afraid that Dipper will start to despise his great uncle for his weakness, for his foolishness and cowardice.

Ford didn't want to lose Dipper's respect and friendship. He also didn't want to lose Dipper's trust.

Unfortunately Bill had to come back. He had to show in Ford's dreams and once again remind him about the worst mistake the scientist ever made. The next day Ford found out that the twins were actually fighting Bill twice. Dipper, on the other hand, found out that his great uncle encountered the demon too, and that news surprised him.

Ford knew he had to do something to prevent Bill from going after his family, so he made suitable preparations. He also knew that he should tell Dipper about his own history with the demon. However, he was postponing it, because he thought that the boy wasn't ready. But the fact was that the one who wasn't ready, was Ford himself. Shame and fear of Dipper's reaction were holding him back.

Ford and Bill!

He immediately regretted this decision, once Dipper looked into his mind and the things he saw gave him the worst possible idea. Then Ford took the mind reading helmet off and threw it aside. The helmet made the curtains go off, revealing Bill's symbols on the walls and made the situation even worse.

Why… why were you shaking hands with Bill? You said Bill will posses anyone so he could get this…

He took the rift. He was actually thinking that his great uncle was possessed.

Why were you really scanning my thoughts? Are you Bill right now?!

The boy reached for the memory gun. Ford tried to calm him down, but Dipper didn't listen. He was constantly backing away, still afraid of his own family member.

Just… just calm down p-p-p…

Pine Tree?! Is that how you're going to call me?!

I was gonna say "please", kid!

Dipper was pointing gun at Ford. He was holding the rift and if he wasn't careful enough, he was going to drop it. But it wasn't the worst part of this horrible situation. The worst part was the look on boy's face – a horrified look of someone who was desperate and could do anything, if Ford would do one wrong move.

Great uncle Ford told me to protect the rift! Get one step closer and I'll shoot! I'll erase you out of Ford's head!

It's me, Dipper! It's your uncle!

And then Dipper said it. The words that he must have read in the third journal.

Trust no one. Trust no one. Trust no one…

He was repeating it like a mantra, as he pulled the trigger. The beam from memory gun hit Ford's metal plate which deflected it and both the kid and the scientist bowed to avoid being hit. Then the beam broke the screen of mind reading machine.

When everything calmed down, Ford put up Dipper and raised him on his eye level. The boy was struggling, but he was no match with a grown-up, fire-forged Ford. The man tried one last time.

Now, now, just calm down. Calm down. Look into my eyes. Look at my pupils. It's me Dipper. It's me.

He even smiled. And that was enough to reassure Dipper that he was safe and everything was fine. Then Ford decided to finally confess to him his story; finally trust the boy just like he trusted him with the rift and the possible danger of it.

Later they were sitting at the table and drinking Pitt Cola. Dipper was still embarrassed about what happened.

From now, no more secrets between us…

Now, when Ford was lying in his bed and thinking about the events of that day, he couldn't get rid off of the vision of scared Dipper pointing memory gun at him. At this horrifying moment he was actually believing that the man in front of him wasn't his great uncle Ford; wasn't the Author of the journals, the one person in the world Dipper admired the most. If it wasn't for the metal plate in Stanford's head, who knew what could happen?

From now, no more secrets between us…

Ford was going to stick with it. He had to be more open with Dipper about these kind of things. He had to suppress the habit of keeping secrets from people.

Trust no one…

After all, he wasn't alone, anymore.

And if he couldn't trust Dipper, then who?