I don't know man
When you're too weak to take a stand and just throw out a phrase like it means something, even though you're not sure what you're saying.
'I don't know man' when your friend asked if you wanted to go to the concert and you were too scared to say no.
'I don't know man' when your mom asked you to do your homework and you just stared at her like she was asking for a million dollars.
'I don't know man' when your teacher asked if you understood the lesson and you just said it because you were too scared to admit you didn't.