You may even think one of your coworkers is a jerk or even a bad teacher. Feel free to think what you want, but be careful about what you actually say. Never ever never say something bad about another teacher in class. You are all working together for the cause of helping other students. You don't have to like each other to do that.
Sometimes students will want to talk about how much they don't like some other teacher at your school during your class. Don't let them. And definitely don't speak in agreement with them.
I wouldn't fault you too much for insulting another subject in class (many teachers talk about how much they hate math, for instance). Just stay away from naming names or making it obvious who you are talking about if you are being insulting.