Smart people know when to move on.

A wise man once sat in the audience & cracked a joke.
All laughed like crazy. 

After a moment he cracked the same joke again and a little less people laughed this time.
He cracked the same joke again & again.

When there was no laughter in the crowd, he smiled and said:  

"When u can't laugh on the same joke again & again, then why do u keep crying over the same thing over and over again."

 Know your ground. live up your life to the point where you are satisfied with it. It's time to move on.