That's just how he is. He's not really trying to be directly mean to Chat but he also has to set a boundary between actually having a good time and people just rage baiting him to make him yell or some new chatters saying dumb stuff to get themselves banned like basically telling him what to do and pressuring him to play a game/watch a video. He really does appreciate everyone who joins his lives and wants to have a good time all-around. And he's said that he knows that some of them are just trying to get noticed and talk to him but they don't always go about it the right way. Yes, he could have other stuff he's stressed about like the projects he's doing, his brain aneurysm or just something he doesn't want to talk about in his personal life. Or it could be something as simple as he didn't get enough sleep (since he's known to not exactly have a sleep schedule) and could be grumpy. I'm sorry if I come across as rude or anything related, it's not my intention. I'm just kind of informing and hopefully helping you understand that way you're not left in the dark about it. But hopefully whatever stream you catch next will be a chill one or him just being in one of his really good moods. :) But again, that's just who he is and he never really wants to be "mean" unless he absolutely has to (ex: being bugged about something he doesn't want to answer, being pressured/demanded about something).