I secretly hope my girlfriend breaks up with me.
Why?
I want to feel justified in venting my anger.
If you do not want to be with someone you should tell them. It is wrong to withhold anger to vent at someone after doing what you want them to.
I know, but I'll look like an idiot if I just start venting and have no real reason to.
I don't think it matters how you look. If you're unhappy with your relationship, break up for an actual reason, not to disguise your feelings.