I write for the same reason I read: because it's all there is for me.
Reading was a joy, a desperately needed escape -- I didn't read to learn, I was reading to read.
Literature simply becomes richer after you've been fired, rejected, stranded, or had to change a few midnight diapers.
Writing is the only art form where a good number of the artists make a slice of their living criticizing one another in print, in public.