Great advice but for every profession and not just creative ones. In my opinion, bad moods often come from something in our lives that we would like to see different. One way to handle it is just to accept that portion of your life. The other way is to understand your problem and work to modify that situation to make it something more in line with your desires. Seeing your situation gradually change would then (hopefully) minimize your bad moods. Whether it's a relationship issue or a job issue you that annoys you, look to see what you can do to make a change.
RE: Don't Be Led By Mood If You Want To Become A Professional Worker