There is a tough problem that creative/artistic people face:

Insecurity.

One way it shows up is in the drive to do too much; anything to prove the worth of the creative person.

The person ends up over-extending, eventually burning out, and ultimately letting people down. The creative person internalises this as a failure of not doing enough, and vows to correct that the next time out, ensuring that the cycle repeats.

"Know your worth" is about much more than charging a sustainable rate.