The following comedy lesson is brought to you by Michael Showalter, The Slipper Room, the F train and Road Runner Internet service…

Michaelshowalter Comedians make fun of each other all the time. Most of the time, however, the comedian poking fun and the target of the poking are good friends and all is friendly. When the comedians don’t know each other, look out. Such was the case Tuesday night at Seth Herzog‘s Sweet showcase at The Slipper Room. Everything was going along smoothly and long as usual during the two-hour affair, with Herzog dancing like a fool, Brett Gelman presenting the angry insult comic Jimmy New York, and Showalter describing the first time he and childhood friend Herzog visited Hoagie Haven in the sixth grade. "He is like a cat rolled up in catnip, because I’m telling a story about him, instead of doing my material," Showalter said. He then followed up with an essay about dating girls with boyfriends, which if I didn’t know better, sounds like it could’ve been the inspiration for his charming comedy, The Baxter. So far, so good. Right?

Tjmiller After some more silliness, including a discussion between Herzog and his mom about her affinity for gay men, TJ Miller (co-star in ABC’s new sitcom, Carpoolers, as well as the cameraman in Cloverfield) came on to close out the show. In his opening remarks, he referred to "Michael Showalter and his one-man, four-act play." Gets a quick laugh from the audience. But that perked up Showalter’s ears, while the rest of his face and body evoked more of a WTF reaction. In fact, he said something along those lines, and in reality told his friends, "This guy doesn’t know me." The word "douche" also may have been muttered/uttered. From the back of the room, Showalter muttered the words "what a douche." Clearly affected by this onstage diss, Showalter even texted a message to Herzog about it. Herzog, though, made the situation more awkward by having Showalter approach the stage (unmiked) to say something to Miller about his diss. Miller didn’t know what to say except to apologize. Minutes later, Showalter confronted Miller again offstage to let him know it’s not OK to diss comedians you don’t know. A few minutes of verbal volleying followed before Miller said "this is over" and left the building.

To repeat this evening’s morning lesson: Comedians make fun of each other all the time. Most of the time, however, the comedians in question are good friends all is good. When the comedians don’t know each other, look out. Because that’s often perceived as disrespect.