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.
This is especially common for the occasional What's Wrong With This Episode episodes. Every now and then for April Fools the show had a contest to give a prize to whoever could point out the most errors. These episodes are guaranteed to be more Big Lipped Alligator Moment than actual episode as the characters turn into puppets, the show is shot entirely in The Sims, actors switch places, or a hundred other random occurrences.
There is also the Drew Live episodes which are essentially cross overs with Whose Line Is It Anyway? in which the entire episode is shot live and the actors will at any random point be forced to ad lib a new line, or break from the show entirely to play out a Whose Line Is It Anyway? improv game.
Daffy Duck appeared in the season 3 finale looking for a job at Winfred-Louder, in the opening scene. After Daffy leaves, the incident is never brought up again. You;d think that if a classic cartoon came into the office, most people would be talking about it for hours on end!
The musical numbers generally come across as this, at least for people used to them. They follow the 1950s musical rules and not the 1990s sitcom rules.
"Funny Aneurysm" Moment: in "Hush Little Baby" when Steve is leaving the house, Mimi throws him a suitcase, saying that she has it in case Steve ever cheated on her. Two seasons later Steve does end up cheating on Mimi.
Ho Yay - Oswald and Lewis. Lewis had to enter marriage counseling with Oswald and his fiancee because he plays a bigger part in Oswald's life than Oswald's girlfriend.
Nightmare Fuel - The puppet segment from What's Wrong With Episode II.
Tear Jerker - The end of "The Bachelor Party" where Drew watches the sex tape he made with his fiancee and the audience learns it's an attempted sex tape where his fiancee realizes she's regained her old weight and breaks up with Drew, saying it's his fault she became fat because she "can't be around someone who loves to eat". At the end of the episode he rewinds it and watches it over and over. Made worse since her parents used this same phrase to describe Drew in an earlier episode but it was played for laughs.