Yes! Just the other day the lady in front of me argued for about 5 minutes with the TSA guy because he wouldn't let her through. The reason? She had printed her itinerary from her email and was trying to get through. She couldn't understand that she needed to get a BP!

Also, I'll add:
-- seat poachers! Those who don't even ask to trade, but just sit in your seat and expect you to take their seat without asking first.
-- seat kickers - I have had grown men kick my seat throughout a flight!
-- people who don't understand that yes, there are people who can board before seating 1 (on UA) and try to block the boarding area
-- people who laugh extremely loudly every 30 seconds while having a conversation on the plane