Can someone tell me why you all care so much about getting on the plane first?

The only time I care to get on the plane before everyone else is when the flight is full and overhead space is limited.

Most of the time, I'd just as soon wait and get on the plane dead last:

- I don't have to stand on the plane cramped in the aisle as long waiting for people sitting in the first few rows that boarded before everyone else to find a place for their things and sit down

- I don't have to spend as much time sitting in an airplane seat when I can be stretched out or walking around near the gate

- I have more time to grab a quick snack or drink to bring on the flight

- If I'm working on my laptop by the gate, I can get more done in those extra few minutes, since I can't use my laptop once I get on the plane until we get in the air anyway

Am I the only one without a "I got on before you" ego?

Edit: (I should add, that if they are looking to give some incentives to bump people, you won't get it if you've already boarded. Just another reason for my list.)