For what most everyone else said. I was a solo artist... I spent most of my time solo leveling up my characters to at the time level 60. Mostly because I play on MY schedule, not someone else's. I had a casual friendly guild that I join up, great people, there to help when I wanted/needed. It was reciprocated. But once I got my third character to level 60, I realized there was nothing left but to sit in Ironforge waiting, spamming for a raid invite, sit around for 2 hours as such, and either log off, or get invited, only to wait another 2 hours for the rest of the spots to fill up while people logged in and out, then finally spend 45 minutes waiting for everyone to get to wherever the raid was going, in the meantime losing a handful of people, causing us to wait another half hour for fillers for those spots, only to get into the raid and sit there spamming whatever key the raid leader said you had to or get kicked.
Whoopie.
It's either that or join a raiding guild which basically dictates your personal life - log in at this time for this raid or else... no thanks - I play on MY terms, not yours.
I quit in January of last year and had no desire to go back.