"I don't know man"
It's used at the end of a long piece of advice just so that if the person takes the advice and things go wrong, the advice giver can't be blaimed for it.
I think you should ask her out, but idk man.
It's the sort of anger felt when you're in an argument and you know you are wrong but you're mad anyways.
Tina got so fangry at me last night when I told her that the moon wasn't actually made of cheese. She kept arguing that it was and that I lied to her.