There are many things that could have happened if things went a little differently. If the world rotated a little different, some things would have never happened. would give anything to turn this into a happy story, but the thing is... The way I see things, there cannot be one. I think that this story was going to end in blood.
There's no saying that they didn't have a happy life. They had a loving mother, a proud father. Yes at times John Winchester can be seen as a cruel father, leading his sons to war. Yes he trained them up to be fighters, warriors. They both had to grow up faster than most children. They couldn't have a relationship with any humans, always hiding secrets. Always on the ran. But think about it... If John Winchester didn't teach the boys how to fight, they wouldn't have survived. He would have put them in danger. John Winchester loved Sam and Dean. I mean, he sold his soul his soul to save one of his sons. What's more loving than that? sacrificing your own life to save another. I do admit some things he did were questionable, some things I wish that he hadn't done. But he was family to the Winchesters and family means everything to them.
There's nothing that a Winchester wouldn't do for family. It's the only thing that keeps them together, as well as tearing them to pieces.
No family is perfect. There's just no such thing as that. Not in this world.
Once the world was perfect in every shape and form but men became jealous and greed clouded their judgement. The seven deadly sins of men rose from the depths of the Earth and were soon consumed by the age of time continued, men had forgotten what used to be.