I fall into the camp that ignores multiplayer game out of hand, and after taking a bit of time to honestly consider why I boiled it down to a single element: Embarrassment. I don't, generally, think that I am very good at playing games. Part of it is almost certainly in my own head: I thought I was really bad at even single player FPS's until a friend explained to me that the mouse sensitivity slider has an actual function, but whenever you start a new game it takes some time to get up to speed*, and it makes me deeply uncomfortable to think that my huge pile of initial losses will be viewed by other people. This is, of course, my brain playing tricks on me again. Thinking that the player on the other end is mocking me to all his friends (because he is able to chat in Google Talk and still kick my ass), or even cares about my existence beyond having someone to play against. Still, as in so many areas of life, the feeling of being judged on your failures is very difficult to overcome, and usually keeps me from joining in multiplayer games (also, finishing my novel, starting a podcast, and posting to forums more often). These might just be my personal issues, so I'd love to know why everyone else who says they ignore multi-player does so?
*This is one thing I have loved about Rogue Legacy. The changes in stats are small enough individually that it seems like I am getting better at playing the game, not just brute-forcing it. If it's true that's great. If it's not, at least they hid it well enough that I feel that way.