NPR's guide to the running gags from the show.
Sometimes hand slaps should be withheld.
3 episodes feature this joke:
Michael rejects Barry's high five after Barry forgets about his wife's death.
Related Joke: insensitivity to Tracy's death
Sources: Joke data compiled by Adam Cole / NPR. Episode metadata from The TVDB via a Creative Commons Attribution 3.0 United States (CC BY 3.0 US) license.