When I'm in first, I certainly never have a problem moving if someone asks to another first class seat (though I do prefer the window, I can easily live without).

On my Fourth of July trip my girlfriend and I had the aisle and middle seat in coach (on Delta of course ) and a man came back with his two sons and they were not sitting together.

First the flight attendant asked one lady if she would mind moving to another aisle seat. She starts huffing and puffing asking them to move her up front to First and so on, finally the F/A just moves her up a couple of rows in coach to another aisle seat and she seemed none too happy about it.

I then offered to move from the aisle to the window (actually I moved from the aisle to middle and my girlfriend from the middle to the window) so this guy would be sitting directly across the aisle from his sons, instead of a row in front of them. No problem for me, I didn't mind at all, but the F/A came back a few minutes later and thanked me and gave me two courtesy coupons (free drink/headset), which I thought was a very nice gesture that I in no way expected for my small act of courtesy!