The wise Man and his Joke

A wise man sat in the audience and cracked a joke. Everybody laughs like crazy.
After a moment, he cracked the same joke again. This time less people laughed.
He cracked the same joke over and over, until noboby was laughing anymore. Then he smiled and said:
- You can't laugh at the same joke again and again, but why do you keep crying and complaining over the same thing over and over again?