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.
Hilarious in Hindsight: While the Shoe Event Horizon was funny back then, the rise of the Starbucks coffee chain means the world seems to be heading the same way in Real Life.
What The Hell, Casting Agency?: Trillian's accent. Seriously, what the Belgium was that all about? Made even stranger by the fact that she could do a perfectly passable English accent, as seen on a few outtakes. Apparently she asked Douglas Adams if he wanted an English accent, and he was so happy with her casting in the first place that he said no, she should use her normal voice. He came to regret this, in part because he realised it wasn't a particularly flattering thing to say to an actress.
Mis-blamed: Many things the fans complained about were Adams' intention from when he first outlined this adaptation - fans should remember that he tried to work in new bits into every new Hitchhiker's adaptation - and much of the script was written by him.
Romantic Plot Tumor: This very movie features a fairly obvious example of this trope, between Arthur and Trillian. The "original" source materials (book, TV and radio series) all handled their past differently, but agreed that Arthur had been briefly interested in Trillian during a single superficial encounter in the past; when he re-encounters her during the story, he displays jealousy at a few points, but not much more than that. By comparison, the movie version features an Arthur who is desperately pining over Trillian, who could have been his one true love had he not been afraid to pursue her, and he spends most of the movie time thinking about, worrying about or focusing on her. This was deliberately inserted by Douglas Adams when drafting the movie, before his death, to increase studio interest and audience acceptance of the movie.
The franchise in general
Adaptation Displacement: Most people are familiar with the series as either a five or six book "trilogy", unaware that it was first a radio program. For those people who know about the radio series, this makes the complaints of the book-only fans about the 2005 movie absolutely hilarious. Also, many fans get the timeline backwards on the novels and the radio series (the novels are the adaptation).
Angst? What Angst?: Trillian barely notices when her home planet is blown up and billions of people are killed. Dent has the decency to be shocked for a few minutes, though once he realizes that he can't quite wrap his head around the magnitude of the loss he starts going into culture shock.
Film version Trish Mc Millan doesn't even find out until late in the story thanks to Zaphod. When she find out, she goes ballistic.
Trish:Love and kisses?!?!
Awesome Ego: Zaphod in all versions except the movie. It's how he survives the Total Perspective Vortex.
Hilarious in Hindsight: Wikipedia. "While it has many errors and contains much that is apocryphal, or at least wildly inaccurate, it is slightly cheaper."
To say nothing of the fact that anyone could wander in and write a paragraph.
It Was His Sled: 42 is the answer to the Ultimate Question of Life, the Universe and Everything.
Memetic Mutation: "42", "Zaphod's just this guy, you know?", "DON'T PANIC"...
Mis-blamed: Many people actually cry Adaptation Decay or They Changed It, Now It Sucks to the various adaptation(s) because they're "not like the book". This is despite that Adams actually approves them himself (and is pretty much involved in the production of them all, see in the movie section.) and he's stated, numerous times, that he wanted them to be different.
