What’s the best advice you’ve ever received?

Caped Crusader suggests that we each “comment on the most memorable quotes and/or advice we have personally heard or received during our lives; not something we have read.”

I think this is a terrific idea, so I’m asking you four you help, instead of providings thoughts for the day today.  Unfortunately, I’ve drawn a complete blank as to my own experience.  I’ll bet you can do better.