Umpires that act like that should be fined. It undermines the game, and that's not the role of the umpire.
I've seen that happen from time to time, and when it happens, and it's obvious, I have to wonder if any disciplinary action is taken against the umpire.
They do go nuts sometimes- I was at a Cardinals game earlier this month and the umpire actually kicked a fan out of the game for giving him the finger. I've never seen that happen before, and I'm not going to defend the actions of the fan at all- in fact the fan should have been kicked out, but I thought that would be something that a MLB umpire would be better served to ignore. I need to also say that the incident happened after the umpire kicked a pitcher and two coaches out of the game, so it was kind of a heated moment. Despite that, I expect umpires to maintain composure no matter what happens.</p>