I also feel badly when a student of mine fails. I not only feel like I let the student down but I feel as if I let myself down. Even though I know I go out of my way, above and beyond to do whatever I can to help the student succeed, I still take it personally. This is one of my own faults, (self-esteem), something I know I need to work on. I need to let students be responsible for their own failures as well as their own successes.
