"A song that describes me" is almost impossible to pick. My former standard go-to was "Loser" by Beck, but that makes me sounds more gangsta (and therefore cooler) than I really am.
"Sexy Bitch" (David Guetta) would be funny, but an arrogant choice.
I love "Not Ready to Make Nice" (Dixie Chicks), but it makes me seem like I'm really angry about something. I mean, I'm generally mildly angry about a lot of things, but there's no specific underlying anger.
"The Underdog" (Spoon) is a good choice, because it's talking to someone who is underestimating the underdogs about the underdogs. I kind of fit both categories, but it's still confusing.
So I will ultimately go with "Last Dollar" by Tim McGraw, even though my song list is OFFICIALLY country-heavy at this point.
And a song I used to love but now hate? "Haven't Met You Yet," Michael Buble.