The Incredible Hulk was one of the founding members of the Mighty Avengers. Yet, it was clear that he did not belong among the other assembled heroes. He was nasty, brutish, and mean, and he made no attempts at hiding his true nature. The other Avengers, Thor and Iron Man in particular, also made no bones about their dislike of him. The Wasp clearly was repulsed by the Hulk’s manner and appearance, and was openly frightened of him. These emotions and inner fears were realized during an attack by the Space Phantom (see this ebook for more detail, summary and analysis of the events of Avengers #2), leading Hulk to leave the team in a fit of anger.
In the history of Marvel Superhero Teams, this incident is particularly significant. While team members come and go with some regularity now, this was the first actual “resignation” and team lineup change in Marvel’s Silver Age. With the exception of a few team-ups, the Hulk would stay Not-an-Avenger well into the 21st Century. When he quits a team, he does it right!
Of course, Hulk would have many other adventures with the Avengers, usually involving the chance to smash Thor in the mouth. Some of the best classic battles in Marvel history involve Hulk and Thor duking it out.
Marvel writer and editor Stan Lee knew what he was doing, of course. The next issue of the Avengers has Hulk teaming up with Namor, the Sub-Mariner (both would later be teammates and occasional sparring partners in the Defenders), to fight the Avengers, who at that point were hunting him down, feeling some responsibility for any damage he may cause while on the loose.
The conclusion of THAT issue would lead Namor to fling a block of ice into the sea in anger at the ways of the land-dwellers, not knowing that this block of ice contained his old war-time buddy, Captain America. The Avengers (in Avengers #4), were at sea, looking to finish their fight with Namor when they come across the (as Iron Man refers to him in the Avengers movie) “Capsicle,” and rescue the Sentinel of Liberty. And, at that point, the Avengers lineup changes again, as Captain America basically replaces the Hulk as an Avenger.