These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
The song "Jaunty Gumption" by Kevin Macleod, which appears as interruption music during his videos for SUPERHOT and Airport Simulator 2014.
He Panned It, Now He Sucks: A number of viewers weren't happy with his video on Metal Gear Rising: Revengeance. They felt that he was wrong about the game being a button-masher, and that he tried to treat the game as the next installment in the Solid series, rather than as a spinoff.
Hilarious in Hindsight: On Dan's "People to watch! (and not in a hiding-in-the-bushes way...)" video on his second channel, he gives a shout out to CharlieIsSoCoolLike and he mentions Charlies outro by Steven Friday and Dan considers himself low-class because he doesn't even have an outro. Come sometime later, and who does his outro?
Memetic Mutation: Dan posts a link to a "mystery video" at the end of most of his videos. Fans will often comment on said mystery videos: "I was sent here by a man who *something that Dan did in the video*." Examples include: "I was sent here by a man who made a nuclear reactor in his bedroom while trying to find his glasses." from a "3 free game Friday" video in which Dan played I Can't Find My Glasses.