Because you don't like the painting anymore.
Because you want to paint but you've run out of canvasses.
Because, just because.
Originally this was a painting with a paper bird collaged to it. As I painted over it, layer after layer, the bird refused to go away. You could see the outline through all the paint. So, instead of obliterating it, I highlighted it.
Simplicity is the removal of the useless and the unnecessary--source unknown