Talking about Captain America 3, so if you haven't seen it yet, beware the spoilers.
Overall, it was a good movie; however, I found the basic premise flawed.
The movie calls out 4 incidents for justification for the Accords; however, 3 of them were completely not the Avengers fault.
1) The Avengers didn't cause the Alien Invasion and the Avengers were formed by SHEILD to fight the alien invasion.
2) The Avengers didn't create Hydra
3) The bomb in Lagos was set-off by the bad guys and would have likely killed more people if the Scarlet Witch had not tried to move it safely out of the way.
The one incident remotely related to the Avengers was Ultron as it was created by Tony Stark. However, that was completely on Tony Stark and not the Avengers in general. (It also isn't clear if it is widely known that Stark created Ultron. And if it is, why hasn't he been sued out-of-existence yet)
After the Accords are signed (or were they, it really wasn't clear), the movie goes out of its way to show that Captain America was right to oppose them.
And the setup for the big fight scene was pretty silly (but I come to expect that from Marvel movies). It was a case of the hero being intentionally stupid. They had Ant-Man. He could have shrunk down, ride an ant over the Quinjet, shrink it down and fly it away.
Going back to the justification for the Accords.
They could have easily listed a dozen or so "not so famous" story lines that took place between the movies. Or even started the movie where it is very clear that the Avengers showing up actually made the situation worse and that they were working with flawed information.
Also, the fact that the Accords came out of left-field and surprised the Avergers was silly. You don't get over 100+ countries to agree to anything without massive amounts of press-coverage.
The "Our Way or the Highway" mentality was also stupid. You don't put limits on "Earth's Mightest Heroes" without discussing it with them first. If both Vision and Scarlet Witch said "no", who the heck is going to stop them?
It was simply manufactured drama to justify Captain America punching Iron Man in the face.