How selfish, stupid, ungrateful, etc. can you get? rhetorical question
A rhetorical question is used to express surprise, displeasure or disapproval that someone has been so selfish, stupif, ungrateful, etc.
They don't realize how much he does for them. How ungrateful can you get?
He will not agree to support us with this problem if he earns nothing from it. How selfish can you get?