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.
Complaining about Shows You Don't Watch: In his book on Gilligan's Island, Sherwood Schwartz describes one local LA TV critic, Barry Humphries, as doing this. Humphries not only wrote a scathing review of the first episode when it aired, but also made angry swipes at it every week in his weekly column, even when his column had so little to do with Gilligan's Island, the attacks would seem to come from left field. Finally, Schwartz invited Humphries over for lunch one day to see if he could find out what Humphries' problem was. At the lunch, Humphries proudly declared he'd only watched the first five minutes of the first episode and that was all he needed to know that Gilligan's Island was a disgrace to TV that needed to be expunged off the air.
Ensemble Dark Horse: Ginger was advertised as the celebrity sex symbol, and Mary Ann was the plain Kansas farm girl. Guess which one the fans actually thought was hottest?
Everyone Is Jesus in Purgatory - The popular theory that the seven castaways represent the seven deadly sins, and that the island is a purgatory for them to work off their bad karma, or a hell constructed specifically to torture them.
Ear Worm - the theme song. As Achewood pointed out, Emily Dickinson's "Because I could not stop for Death" fits the theme song... as do "Amazing Grace", "Auld Lang Syne", and the first verse of the first English Pokémon theme.
The aforementioned works are all written in Ballad Meter if you're wondering.
Ho Yay - In one episode both Gilligan and the skipper both think the other has been turned into a monkey. It Makes Sense in Context. What is the first thing they do when they see the monkey dressed up in the other's clothes? Strip it naked, of course.
Apart from that, consider the Skipper's way of addressing Gilligan as "Little Buddy."
Hollywood Homely: Mary Ann. Even lampshaded on The Simpsons when the network executive wanted someone "ugly" like Mary Ann, not "ugly ugly" like Moe. (Even though none of the other Gilligan characters ever referred to Mary Ann as homely; more the shy, Girl Next Door type.)
Nightmare Fuel: More than one viewer felt that during the show's "Jack and the Beanstalk" dream-episode, Alan Hale was genuinely frightening as the giant.
"Ghost a Go-Go" uses the Bedsheet Ghost trope (albeit it's a man pretending to be a ghost) and while the episode mostly keeps it from being Nightmare Retardant, it doesn't quite reach this trope. There is, however, one scene in the episode where Gilligan is woken up by the "ghost", opens the blinds, and sees the guy standing right outside his window staring at him.
The Problem with Licensed Games: Why someone thought this would make a good video game is one of history's great unsolved mysteries, but a NES game was made. It's generally considered one of that console's worst titles.
Unfortunate Implications: Played with; while there is a spear-carrying bare-chested native with a bone in his nose holding a shrunken head, he's unambiguously pale with face paint that resembles Nerd Glasses.