Perfectionism is the Achilles heel of creativity. As an artist, I don't actually agree with the results. You have to move towards progress; you have to make 100 bad gesture drawings to make a good one, 50 bad paintings to make a decent one. It's practice, it's mileage, and you can't spend all your energy on a painting when you don't have the skill to execute it. I've put in many days and nights on art that I've worked on for hours and hours and hours, I can be painting and think it's amazing, and I'm almost satisfied. A day later, I come back and it's absolute crap. I'd be angry, angry at myself, painfully knowing that all my works have been like this and will probably be like this all my life, a few days go by and I realize it's not that bad, but I can clearly make out its flaws that I don't have the ability to correct yet. At that point, I move on, maybe I'll try again in a few years. What if there's a deadline? You have to accept work that you're not completely happy with. And you have to be okay with that, drawing would be even worse for me, unhappy with its amateur quality. Being a perfectionist, constantly being angry at yourself, working tirelessly on small mistakes without being able to see the bigger picture... no one would be happy that way. I've dealt with perfectionism, both in piano and art, and it's slowed my progress, destroyed my self-esteem, and, yes, made me unhappy. I've gotten a lot further by moving forward and accepting small mistakes, while working on the fundamentals and my overall skill level. Accept that you can't be perfect in every little detail, work on the bigger picture and you don't have to be an "unhappy artist."