Is there a bigger boost than one of your favourite musicians liking your art? Probably not. The only greater form of positive reinforcement would be one of my favourite painters like Gericault coming back from the dead and telling me that he liked the way I drew the two men from Raft of the Medusa (which would lead to an in-depth conversation about The Dead Weather), or meeting any one of the sideshow wonders who have inspired me.
Maybe it just doesn't take much to boost my self esteem in my art. Though, it didn't take much with that foxhole drawing to boost my opinions of it. I was already pretty pleased with it. But hey! The person whose lyrics inspired it likes it too. That's swell. Real swell.