I mean, there's the standard TV show stupid where characters have to tell each other things that they already know, so that we the audience can catch up on what happened since last season. Fine. Normal TV stupid.
There's the stupid of watching combat scenes - streets somehow devoid of cars except for those belonging to the villains; martial artists spinning into HTH despite facing their opponents and having a clear path between them (you don't turn your back on an enemy if you don't get something from it - sure, spinning around may get you leverage for an attack, but nobody did that); old Western-style one-shot-insta-death bullet wounds (except, of course, for any character with a name), and so on. TV violence stupid. Fine. Normal.
There's the interpersonal drama stupid, which includes both "let's talk about stuff that we would never directly say, except for the audience to catch up" and "let's make sure the audience has been informed, AGAIN, of exactly who has what relationship with whom." Bleh. Fine. Gotta throw in some backstory exposition for the new watchers. Then there's the mind games and secrets bullshit, where everyone pretends that they haven't spent five years learning that you need to rely on your teammates and that means telling them when something weird is going on. Fine. Emotionally constipated characters in order to stretch out the tension.
( There's also spoilerific stupid, so I'm putting that behind a cut. )