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.
Foe Yay: Dan and Impostor Dan, played up even more in Dan Vs. The Telemarketer. Impostor Dan basically stalks Dan, steals his identity, breaks into his apartment, chloroforms him, calls him a "man cookie," and not to mention the scene where Impostor Dan breaks into Dan's apartment dressed up as a cat and taunts him around his bed.
Hilarious in Hindsight: One episode has Dan trying to convince the police that Elise's parents are in the mafia. As proof, he records and splices a conversation they have about their cupcake business. He explains that "cupcake" is the new slang for "kill". In the My Little Pony: Friendship Is Magic fandom, thanks to a notoriously gory fanfic, "cupcaked" is occasionally used as slang for being gruesomely killed.
Ho Yay: Dan has expressed to Chris that he should have never gotten married, his distaste for Elise, clinginess to Chris ("Why was your phone off?...This is not ok. You never turn your phone off, ever again. Promise me!...PROMISE! ME!"), seems to really like touching Chris's mouth, knows Chris well enough to know his grooming habits from his knock, and had such dialogue gems as: "Seriously, if this doesn't work, I'm leaving you." followed by a quickly whispered "I would never leave you." and while gloating to Elise: "Possession is nine tenths of the law, I'll have you know. Technically, Chris is mine now." Chris is also the only person in the universe Dan seems willing to show any sign of caring or affection for, however minuscule the gestures may be (this being Dan, what's common courtesy to the rest of us is angelic from him). But the kicker for this trope has to be:
Dan (talking as Chris): I love you.
Dan as himself, shyly: Um, I...feel...somewhat warmly towards you.
And in "The Wolfman", Dan's response to Chris's heart-shaped locket containing a picture of Elise? "Hey, that's not me."
Unless you have really good insurance, you don't get to see an actual doctor, but an actor the hospital secretly hired.
Your children's dentist secretly damages your child's teeth to get more money from you.
That guy that runs the gym? He's a cyborg. So are most of the other buff people working out there all the time. And they're all planning to rule the world and force you to repower them up, under punishment of taser. And they plan to replace you with a better looking cyborg of you. Seriously, the gym has a LOT going for it.
"The High School Reunion" features songs similar to many of The Eighties' greatest hits.
They Just Didn't Care: The animation is seriously lacking in a lot of places. In one episode, Dan's arm becomes a detached floater while poking Chris, while in another his shirt is backwards for a good few seconds, and in another, Chris' steering wheel is on the British side of the car for most of the episode! Heck, in one, Chris makes pancakes on and with NOTHING! The backgrounds are usually empty, too, like how the drive-through at Burgerphile can be so crowded, yet nobody is inside save for one cashier; and no wonder there's so much traffic where Dan is...nobody's driving any of the cars! (Then one has to wonder where the honking comes from...)
Dan himself, especially among his (surprisingly numerous) fangirls.
What Do You Mean, It's for Kids?: The Hub's programming is very much child-friendly stuff, and while some series on the channel do have quite a bit of dark material, Dan Vs. is perhaps the only one who owes its darkness to Black Comedy. This show would likely feel more at home on Cartoon Network fighting with Regular Show over which "kid-friendly-but-really-not" cartoon is the best.