Failure
Success is a lousy teacher. It seduces smart people into thinking they can't lose.
Lost the race? Check your shoelaces, then run another one.
Fall down seven times? Good. You now know seven places to avoid.
The best teacher is experience learned from failures.
I do not believe in a fate that falls on men however they act; but I do believe in a fate that falls on man unless they act.
One does not discover new lands without consenting to lose sight of the shore for a very long time.