For me, being in a band used to mean - for the biggest part - getting to hear my songs w/ proper instrumentation, completed. Since I didn't own or play drums, or a bass, and didn't have any sophisticated set up to record the songs, there was no other way. I never cared much for live gigs after I had done that a few times.
What I dug when playing w/ musicians is that they could improve my basic ideas. Whereas I would think of a very simplistic/repetitive drum pattern or bass line, my fellow band members would take those ideas and breathe life into them.
What I didn't like half as much was the occasions when their creativity started to claim too much space. I'd always hear every ideas, but in the end, when you have a very clear idea of where you want a song to go, you sometimes have to say no, and I hated playing dictators.
Fortunately for me, according to a few people who used to hang out w/ us at rehearsals, I have a gift for non-verbal communication, even when I think I'm doing my best to keep a poker face while politely listening even to our drummer's most inane suggestions. It seems the temperature in the room just drops...
Still, when it works, nothing beats a real band's chemistry. One example which always strikes me is the old Alice Cooper band vs Alice Cooper. There's no doubt that the solo albums benefited from the better players, but the music itself was way more exciting w/ the old band.
Even when listening to electronic music like the early NIN, the old The Cure albums or old Skinny Puppy - you can hear that it's not just another gun for hire in the back. Those guys have meticulously crafted their parts and contributed to the picture as a whole.