I've written major portions of many songs in my sleep. I could never have come up with some of the lines if I was awake. Describing a paralyzed elderly woman at a nursing home where I sang who could only tap on finger in time with the songs, but otherwise was completely expressionless I dreamt a verse with the lines:

"And somewhere inside her there's still that young girl
With a tortoise shell comb in her hair
And sometimes the memories come back with a song
As surely as if she were there.

Maybe I'm smarter when I'm asleep.