He who laughs last is generally the last to get the joke.

Related:

• He who laughs last didn't get
  the joke...
• Bocklage's Law:
  He who laughs last probably didn't get the joke...
• He who laughs last probably didn't get the joke. -
  Bocklage's...
• He who laughs last is generally a
  bit slow...
• He who laughs last probably doesn't understand
  the joke...