15. Disney Doesn't Want You To Know He's An Alcoholic
If you've only ever seen Tony Stark in the movies, no one would blame you for not realising that he has a serious drinking problem. It's something which Marvel has avoided dealing with, despite the fact that they at least hinted at the idea during Iron Man 2.
Shane Black actually wanted to adapt Demon In A Bottle (the storyline in which his alcoholism is revealed) for Iron Man 3, but Disney wouldn't allow it because of the large number of children who watch the Marvel movies.
In the comic books though, it's an issue which still occasionally comes up, especially as Tony has relapsed at least a few times over the years.
6. He Once Rebooted His Brain
Following the events of Civil War, many fans started to hate Iron Man. The majority had sided with Captain America, and Tony Stark was often portrayed as an antagonist hunting down the team of New Avengers which included fan-favourites like Bucky and Spider-Man. In a bid to rectify this somewhat, Marvel had Norman Osborn take over S.H.I.E.L.D., and put Iron Man on the run.
To stop the villain learning his secrets, Stark "rebooted" his brain and gave himself significant brain damage in the process. However, a back-up existed which was created prior to Civil War, redeeming him somewhat and giving him a fresh start.