One of the best workflow/mindset pieces of wisdom I’ve heard came from a friend of mine who was working as an animator at the time. They were under a ridiculous time crunch, and were pumping out animations and renderings around the clock. He said that, because there were so many characters, shots, scenes and environments to be done, he realized that every one can’t be his masterpiece. It wasn’t succumbing to failure. It was understanding that in his lifetime he’ll do so many animations there are bound to be a few clunkers in there.
Recognize you’re unhappy with your work, understand that bad sketches are bound to happen, move on and don’t dwell.