Personally, I don't think "loosing it" is ever a good thing. Therapy is only 1/168 of your week. You need to be able to leave at the end of your hour and go back into life.

I do think it's important to stretch your comfort zone from week to week. Take a chance and say something that you didn't want to say, but don't force emotions. Vulnerability can have a huge price tag, so it's important to be able to contain the excessive emotions it produces when needed. .