Do not let what you cannot do interfere with what you can do.
Don't give up on your dreams, or your dreams will give up on you.
It isn't what you do, but how you do it.
If you don't have time to do it right, when will you have time to do it over?
Be more concerned with your character than your reputation.
I think the teaching profession contributes more to the future of our society than any other single profession.