Funny: Seeing a first-year associate at the urinal in the men’s room and playfully smacking him on the ass three times while yelling “Woo-Ha! Woo-Ha! I got you ALL in check!”
Not Funny: Realizing in the middle of the third smack that he is not, in fact, that first-year associate, but rather, a partner you’ve never met before because he's been on vacation and you don’t go down to the 58th floor much.
Possibly, But Probably Not, Funny: Quickly posting about it in hopes that your willingness to take ownership of your mistakes will somehow overcome this.