I dont know, I'm not a Doctor
A way to say you're too dumb to understand the problem and don't want to admit it.
'I don't know, I'm not a Doctor' when I told him he was being a moron.
'I don't know, I'm not a Doctor' after I told him he was being a loser.
'I don't know, I'm not a Doctor' when I told him he was being a failure.