The athlete who says that something cannot be done should never interrupt the one who is doing it. Be more concerned with your character than with your reputation. Your character is what you really are, while your reputation is merely what others think you are. There's no great fun, satisfaction or joy derived from doing something that's easy. Failure is not fatal, but failure to change might be.
Happiness begins where selfishness ends.
Do not let what you cannot do interfere with what you can do. Earn the right to be proud and confident. Don't measure yourself by what you have accomplished, but by what you should have accomplished with your ability. Discipline yourself, and others wont need to. It isn't what you do, but how you do it.