And the overall attitude, including what the asker is willing to give up. If you're trying to get seated together, you should expect to trade your better seats (if there's any difference) rather than trying to get your whole group into row 6 on an A320, for example.

If anyone is already settled into my seat when I get there, I'm much less likely to be accommodating because I resent the not-so-subtle effort at coercion. On the other hand, if the pax immediate stands up, says "I was wondering if you'd be willing to swtich" and makes it clear that I can say no, then more inclined to say yes.

Of course, if you're asking me to swap an E+ aisle for a row 30 middle seat, you'd better throw in some $$$, too.