I can, and will cheer on for the tokusatsu heroes to beat up the villains most of the time. But what I don't cheer for and, in some case, actively dislike is when one of the good guys is using violence toward another one of the good guys, especially if not reasonably provoked. (I'm not talking about the case where the character is being violent as a result of being brainwashed or some bizarre personality change or being under some outside influence he/she cannot control.) Yes, I get that sometimes it's inevitable. People are different so frictions exist, even among the heroes. But I guess I prefer the friction to not be so physical, if possible. Barring that, I want to see actual good reasons for the violence, and some consequence toward the person who uses it. (Because it seems to me that most of them get away with being violent.) I think I just have a problem when the violence is thrown in just for some emotional scene the script demands (shock value, maybe) and/or when it is horribly out of character. Especially when done against a woman or someone who wouldn't and/or couldn't fight back. I remember this one show that has been above average, and then the hero is slapping the heroine's face for no reason, no built-up that I can see. Granted the show was made many years ago, where that kind of attitude probably was...more tolerated, but, well, I don't live in that time, so that scene alone almost destroyed that show for me. Anyway, I've since come to some terms with it, but still not in any way can say I would not skip that part if I ever re-watch the show.
There have been other instances of one-sided violence toward own teammate/family in other shows that made me somewhat uncomfortable when I saw them, but all of them were no where as bad (to me) as the one I just talked about. Furthermore, I think I wouldn't be as affected if similar instances happen in anime or something not using real actors to portray the characters. (That still depends. Realistic anime will always bother me with their use of violence. Not so much the ones clearly intended to be parody, satire, comedy, or other kind of not serious piece of work.)
::Sighs:: It's just something I have to get off my chest. Sorry that it's not that pleasant a subject.
EDIT many days later: some Ultraman Mebius spoilers in the comments (I almost can't comment/post without inevitably mentioning/referencing Mebius in some way, shape or form...).