One time I wasn't catching anything for nearly 30 mins and when the blinds passed me I put on post/fold and went to smoke and come back just in time to see myself fold AA. That has happened more than once but on some I'm glad because I would have been beat and some were hands that flopped cards I would have had to call with but missed. But I have folded many small PPs pre-flop, because of the amount of the bet or raise. And most of the time I would have lost.