Boris Becker was known for his devastating serve in Tennis. Andre Agassi returned that serve — especially for the points that mattered.
Agassi had an advantage. He noticed that Becker would stick out his tongue in the direction he was going to serve.
What Agassi did with this information is remarkable: He consciously ignored it.
During normal play, he would intentionally not use this advantage. Agassi met Becker serve for serve, playing it by instinct and skill. He did not want Becker to cotton on.
When the tiebreakers and match points came around, he would use it, and swing the match in his favour.
To have an advantage and not use it — that is strength and wisdom.