1) angry/ annoyed pax who make it clear that they are angry/ annoyed to anyone and everyone on the plane
2) separated pax who are both in middle seats who get on the plane before me and decide that I will be happy to trade my front of the plane window seat for the other middle (invariably in the back of the plane)
3) seat-kicking pax... actually, the parents of the seat-kicker who say, "oh don't mind him he's just spunky!"
4) smelly pax
5) non Group1 who boards with Group1