There's a sort of... 'curse' in professional circles, that if (for example) a client needs you to do a drawing of a cat. So you do 5 sketches of different types of cats so the client can pick which one they like best. You love 4 of them but hate one of them, the client is guaranteed to pick the one you hate.
As for screwing up, you learn more from one piece you FUBARed than 10 piece you did perfectly. I bet you learned a lot from your drawing and your mistake?