JPB, passenger weight distribution does not matter on a 757 or 737-800. Actually, it would probably help the weight distribution to sit away from the two fat women.
Jeff, you would be well advised to not start an argument with flight attendants on any airline. I'm not talking about the first time she came around and told you to fasten your seat belt, I am referring to:
<font face="Verdana, Arial, Helvetica, sans-serif" size="2">When she comes by again, I ask her how they would even know if I wasn't in
my assigned seat.</font>
Next time, keep your mouth shut, and when you see an empty seat, go sit in it.