My old man only ever gave me two pieces of advice:
1. "Always take a handkerchief on a date,"
2. And, well, shoot, the other one is unpublishable.
My favorite, however, is the pessimist's variant of the old saying, "A walk of 1,000 miles begins with a single step":
I could cure cancer. I could conquer the world. I could bring joy and happiness to all the people around me. If only I could get up out of this chair . . . .