He’s such a monastic character and he has such a quotidian approach to his existence, I imagine when he wakes up in the morning, there is a routine. Part of that is in his nature, part of that is just to keep his sanity, and that all kind of goes out the window a little bit after Captain America: Civil War. You see a guy who doesn’t stop caring but just puts down some of that obligation.
I don’t think it’s in his nature to be too much of a loose cannon, but there’s a lack of formality. He’s checked all that at the door and he’s gone inside himself for a little while, and as a result, he’s a little irreverent and maybe even a little dangerous. – Chris Evans on Steve Rogers in Avengers: Infinity War