 Fake it till you make it. It's one of the most fundamental truths of human nature. It may not be a catch-all cure for depression. I'm not saying it is. But there are certainly worse treatment plans on the market. I'll tell you that much. Now, if you allow your feelings to entirely dictate your behavior and you use them to justify slacking off, not taking care of yourself, not taking care of your responsibilities, soon you'll be caught in this self-defeating spiral that becomes harder and harder to escape from. Not brushing your teeth in the morning is the first step towards that spiral