Every time I fly I see so many people putting multiple large bags up in the overhead bins when they are not sitting in bulkheads. Its so selfish. Nobody wants to have to check their bag because there is no more room in the bins. I always travel with 2 items and I always put one under the seat in front of me. After takeoff, I can stretch my legs out by pulling the bag out from under the seat. Its not so hard to be a little courteous to our fellow travelers because we are all just 1 delay/run through the airport away from being that person.