The worst type of airline passengers

We've all seen them: The people who clog the aisle while boarding an airplane. Why, oh why, don't they just sit down so the plane can take off on time?

In a slight turn of the tables, I thought I'd take a look at what makes the worst type of airline passenger from the standpoint of people who work on a plane or in the travel industry. After recently detailing the worst ways to interview for a job, it seemed like an interesting way to look at a profession from the other side.

We've all probably had the worst flights of our lives, and these are the types of passengers that can make them a lot worse for employees, as well as passengers: