Isn't it so that when you are happy and enthousiastic you would choose different colours and maybe even different shapes than when you are depressed?
When I'm down or worried all I make are dark and moody images. When I feel on top of the world they tend to be (too) light.
But that still leaves a lot of images that don't belong to either. I guess the swing in the emotional field is in the middle then.

Yvonne