Well, Nader's in the wrong here, and to some degree it's armchair-quarterbacking, but I think the reason many people 'hate' the airline industry so much is that there are so many things the airlines do poorly that they could obviously do so much better, without much effort or cost.

Staff that are rude for no particular reason, aircraft with buy-on-board running out of food, lousy communications, "seat sales" with no seats available, doing an aircraft change and throwing away all the seat assignments, showing a Disney movie in a flight full of business travellers... and on and on.