When Bruce expresses anger by way of a genuine stripping down, it is ironically enough a sign of his trust in you. It is an indication that Bruce considers you someone it is safe to be angry around, to feel normal around.
When Bruce is around someone he willingly sasses or straight up cuts down to size, it is a sign that Bruce has come to recognize that the individual in question doesn’t see his anger as a threat - but rather just a normal human response to pain and frustration. They are someone who won’t wince or quake when he’s angry but will stand their ground, because its okay for Bruce to feel things around them and that’s why Bruce actually showing his anger with or around someone is a huge display of something deeper.
Bruce hates being winced from. He can’t stand it when people flinch from him - because that just further compounds in his mind that he’s become a monster. People quaked and winced from his father - not him. Never him. People were never supposed to be afraid of Bruce Banner. So now, when he gets angry, he hides it even more because he is literally afraid to get mad - not just because of the other guy, but because of the pain it causes him every time someone near him flinches because he actually said something cutting.
Even Wanda supports this. He was pissed, and SURROUNDED BY PEOPLE HE TRUSTED BEING ANGRY AROUND. But more than that it was proof. Proof that he was human. Proof that he was perfectly capable of being ANGRY and not going green. Perfectly capable of KICKING ASS without going green. So it was important then too. Wanda saw him as a monster - Bruce chose to prove that he wasn’t by utilizing the very thing that makes him one against her. Bruce showing his anger is always a sign of something bigger and deeper. It’s never just an outburst.