The thing that polarises singers and musisicans is, as has been pointed out elsewhere, this: singing a song is an ego-trip, and you do it yourself personally (with or without others joining in); playing a tune is something that everyone does together, and if you're not the ego-trippy kind and you hate the thought of being alone in the spotlight where everybody will hear the mistakes you imagine you'll make, then you have the security of being simply an anonymous and invisible part of something much bigger. You can't easily have both situations in one session, but that doesn't mean one is better than the other: horses for courses, I say. (And if you don't like that, I'll say something different!)

Steve