I used to do a lot of travelling. I learned early in my life that just because you have an assigned seat, doesn't mean you'll always get it when you're one of the last to board.
Also, board early, and you get the overhead bin above (or even a little further forward) instead of not having control of where your bag is stashed.
It also pays to get a seat in the front of the plane so you're one of the first off. One of the first off means one of the first to customs.
I've always managed to get the first row seats in the main cabin when I got stuck back there.
I travel a lot. I'm in the industry. I'm the one who boards when told to, and I'm usually one of the last off the plane. I prefer a window seat as I don't like people climbing over me when they want to leave their seat.
Why the rush to get off the plane first? Just to join the immigration queue. I'll take my time, have a chat with the crew, wait for the queue to go down, pass immigration, and by the time I've done that, my bags will be waiting for me on the carousel.
Airports are not a place to get stressed...........Too many stupid people work there and they have no time for stressed people. Before people get offended by that remark, think about this. How many school kids sat at their desks daydreaming that one day, when they grow up they want to become a TSA officer!