This had sat on my computer for over a year, and I needed to post something fluffy. Here you go!
Tony considered himself a simple man. Well, as simple as a billionaire-playboy-philanthropist can be.
He loved his lab, his kid, and his plethora of suits that allowed him to save the world with more style than the Boy Scout or Green Bean. Oh, and Pepper. Pepper was definitely at the top of that list (and no he didn't forget his fiance in favor of his wonderful, wonderful toys).
But his lab held a special place in his heart - it was his refuge, his kingdom, one of the remaining things related to Howard that brought him joy. The team learned that unless your name was Tony, Kid, or occasionally Banner, you didn't come into the lab on pain of repulsor blast. Clint still sends him glares about that one from time to time, but the little shit deserved it for putzing around with the new stingers Science Bros. and Company (Peter) were working on to gift Natasha with on her birthday.
Not to mention all the spitballs Tony put up with because of Clint's immaturity in the matter. He was still finding them scattered about the tower six months after the ordeal.
But, the point is, unless you wanted to unleash the Wrath of Stark, you didn't go near his baby.
Which is why Tony was surprised to find Thor of all people sitting in there one day. He was wearing one of those casual, sleeveless robe thingies and a pair of tight pants - his usual not saving the word attire - with his blond hair pulled up in one of those weird bun things all the hipsters at Starbuck wore. The god still looked every bit the royal warrior, even bent over one of the governing breadboards for his latest suit.
He coughed, causing Thor to look up and give him one of his big, squinty smiles that made him look like a bunny. Tony's eyebrow rose, unimpressed. "You got ten seconds to tell me what you're doing in here with my toys, Point Break."
One of his little soldering tools was placed on the counter as the Thunderer languidly walked towards him. He blinked, surprised that Thor had the finesse to use his equipment for whatever his endeavor was. "Anthony! Friend Banner informed me of a glitch in your suit and I decided to see what I could do about it."
Tony could feel the little vein in his forehead only the kid and Cap managed to aggravate. Thor, the team muscle and powerplay, decided he could just waltz in here and screw up his new armor more than it already was. He sighed, pushing past Thor to see how much irreparable damage had been done.
So imagine his shock when not only was everything in tact, but the part Thor had been working on was skillfully removed without a single nick or scratch. It was better than the kid's work on some days.
He probably said something real intelligent - like "Huh, what, how?!"
"Your science is not so different from the early stages of the Destroyer," Thor said sagely. "I studied the plans in my youth, so when Friend Banner mentioned your glitch, I decided to take a look."
Tony blinked, dumbfounded.
However, when he booted his suit up for the next trial run, the energy drain had been righted; Thor even went a step further, making his new suit the most energy efficient piece of tech he had. Reluctantly, Thor was allowed into Tony's lab, but only under his or Banner's supervision, and never alone with the kid.