I've run into such people as a performer - finding offense at the most benign issue. Some people get pleasure from feeling offended and find they can elevate that feeling if they gripe most professionally and publically. Others find that they can get much more then they paid for if they do the same. The former is a sickness of the mind - the later may be that coupled with a need to get somethig for nothing.

Still others shop lift ... what craziness inhabits our human nature, eh?

;-)