Some serious joke

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”