Hiding
Each of the Avengers has something they don't want the world to know. Bruce would prefer if everyone remained oblivious of his connection with the green-skinned monster. Natasha leaves the room when someone talks about Brasil. Clint pretends he isn't aware that he does have a brother who's alive. Thor's face is pained every time someone mentions Loki or a threat to Earth's safety. Steve wishes nobody knew how he lied to get into the army, and he loathes answering questions about the serum.
Neither of them is really a bad person, they're just all full of aspect and takes and angles and everyone who looks at them sees them differently.
Tony brings the art of hiding to a whole new level.
He doesn't tell Pepper or Rhodey about the poisoning, that he's dying. He doesn't let anyone know about nightmares, even after all those years; he just sometimes wanders barefoot around the house. He doesn't share the fact that he needs to sacrifice himself for Manhattan, they can only guess when it's a moment too late. Every second, he pretends to be a genuine bastard so that no one would past the mask and see how vulnerable he is.