Today I watched a YouTube video of a Roomba rolling and tripping its way through an obstacle course. The video was shot during a student robotics challenge at UC Berkeley, and it’s pretty much exactly what you’d expect when you hear the phrase “Roomba obstacle course.” So what stuck out to me wasn’t the little machine failing to complete simple movements, but the background noise: the person shooting the video, or maybe the person behind them, is laughing. Loudly.

It’s a hiccuping sort of laugh, one that seems to get stuck in the man’s throat and emerge seconds later, sloppy and joyful. At first I was irritated: I’m just trying to watch this dumb Roomba fall over, and this guy is cackling like he’s got something to prove. I couldn’t focus on anything else. I could’ve muted the video to watch it in silence, but 30 seconds in, the laugh had already grown on me, and I started waiting for it whenever the Roomba couldn’t manage to thrust its little plastic body over the ramp.

After watching the entire video — which, in all honesty, doesn’t have that many appealing qualities — I realized why this mysterious, annoying giggle made the video work. And it’s a characteristic more often associated with dated TV sitcoms than with internet videos: the laugh track. This time, the laugh track consisted of just one noisy person, but it was better than any chuckle reel on Frasier or Friends. Then I realized something that I can prove to be true: most amateur viral videos are improved by their unintentional laugh tracks.

Television laugh tracks are often thought of as one of the worst sitcom affectations. They’re fake and robotic, beginning and ending with a stiltedness that never accompanies real human laughter. They’re indicative of a lack of confidence in the joke at hand — a blunt reminder that it’s time to laugh. Internet laugh tracks, on the other hand, are real. They’re not scripted, inserted after-the-fact by a production team, or created by a computer. It comes down to artificiality vs. sincerity, and laugh tracks are often the most sincere parts of viral videos. When going viral now comes with dozens of how-to guides, laughter is refreshingly spontaneous.

There are two common types of internet laugh tracks: the Bystander Laugh, and the Character-Breaking Laugh. The Roomba video features a Bystander Laugh. So does this video of a cameraman laughing at a Fox reporter who gets called “weather boy” by a surly child. Another perfect example of the Bystander Laugh is the Snake Lollipop Vine (RIP), in which a young kid, apparently sitting in class, takes a lollipop out of his mouth and offers it to the snake wrapped around his fist, who licks it.

When you watch the video, you can hear a girl (probably the one filming) laughing in the background. As the camera zooms in, she’s just kind of nervously giggling, but her laughter builds once the snake actually sticks out his tongue. The whole thing doesn’t work nearly as well without her. Try watching the video on mute, and you’ll see what I mean: the video is funnier with the laugh track. Once the Vine got popular, someone layered the chorus of Natasha Bedingfield’s song “Pocketful of Sunshine,” over it, probably assuming that this would be even funnier. A boy and his snake, set to an inane 2009 pop song with lyrics like “And nobody cries / there's only butterflies”? Hilarious!

Wrong. The only thing the song addition achieves is destroying the laugh track, which we’ve already determined is vital to the video’s success.

The Lollipop Snake Vine actually straddles both genres of internet laugh tracks. If you pay close attention at the end of the clip, you’ll notice that the boy with the snake is just barely managing to suppress a grin. This brings us to the Character-Breaking Laugh. This kind of laugh track usually comes from the subject of the video, or someone playing a role for the cameras. Consider the old time Twitter classic Damn Daniel. (Apologies if you thought you were done considering it forever.) The “narrator” whom we all now know to be Josh Holz, made the video a success by affecting this strange, round-voweled accent. At around 13 seconds into the video, Holz loses it:

Daniel’s laughing, too, almost the entire time, but it’s Holz’s voice that matters. The pretense is gone, and Damn Daniel gets even better because it was obviously only ever meant to be fun.

The downside to all this is that once a video gets popular enough, its characters often hit the daytime news circuit, a platform known for artificial lighting and plastered smiles. Daniel and Josh eventually appeared on an episode of Ellen, a show equipped with its own audience laugh track complete with a professional hype person cueing when to react.

The artificial world of studio television might try to feed off a viral video's success, but there’s a reason it so rarely translates well. The lights, the camera, and the army of PAs can’t replicate the essence of the internet video laugh track: sincerity.