Sure, I mean my issue is a bit more specific that I can't buy Mark Ruffalo as a genius of really any kind, and whilst he can do angry/bitter he hasn't really pulled that out for Banner. He's a very good actor and he's got a lot of range (c.f. his great performance in Poor Things, loved it) - he definitely doesn't just have to play nice guys, but I would personally say, aside from the gritty performance in Zodiac, in his performances as detectives or scientists who are supposed to smart (and the Zodiac guy is more just normal), he's been at his least convincing/compelling (which is still considerably above average, I must admit). With Banner he's playing him super-charming, which I appreciate him as a choice to differentiate him from various naughty word movie scientists, especially Marvel ones like Stark or the normal Reed (I presume Pedro Pascal will also tone down the naughty word factor on Reed though), but like I just don't buy the anger as alongside that. He's been great lines and delivered them with gusto, but like, I just do not believe he is, in fact, "always angry" (or a genius). I also really do think a more genuinely angry-feeling and brilliant-feeling Banner, like the one Norton did would have sparked off RDJ's Stark more. In fact, that might be part of the issue - I feel like Norton's Banner would have kind of overwhelmed/swamped RDJ's Stark, so maybe that sort of thinking helped inform some choices here.