There's nothing more painful than something that's superficially upbeat but you can kind of tell behind it that there's a cynicism, or even a bitterness.
Collaboration is much like a birth. The song that springs forth resembles each one of us to a degree, but it's the kind of thing that would never be born from just one of us sitting down with a guitar.
I played with the same band for years and years and there's a beauty to having one solid core that you keep exploring. On the other hand, it's nice to throw yourself in different situations where you find out things about your own resources.