5. You’re a lab experiment
Movie: The Avengers
Steve Rogers and Tony Stark butted heads from the moment they met each other. It was to be expected considering that they are two different people. The first time they really went at it was on the S.H.I.E.L.D. Helicarrier. Stark was saying he was okay with Bruce Banner letting off a little steam. For obvious reasons, Steve Rogers wasn’t okay with it and told Stark to back off. Stark said that he was starting to wish he’d make him. The conversation gets worse from there.
Steve calls out Tony saying, “You may not be a threat, but you stop pretending like you’re a hero.” Stark replies with a pretty harsh response. “A hero? Like you? You’re a laboratory experiment, Rogers. Everything special about you came out of a bottle.”
They may have been respectful during missions, but it’s doubtful they were ever really friends. Rogers didn’t like the person that Tony Stark was and they always bumped heads. They’re just too different. This was the moment when every comic book fan realized that the Marvel Comics series Civil War would be coming soon.