Three wonderful episodes followed by a terrible ending but the next episode makes it better with an explanation that can range from simple to extremely complex. The incredibly long hiatus has driven the fandom insane. Very good at noticing things. One fangirl could probably list 389 reasons why it is factual that John and Sherlock are gay for each other. (Though anyone outside the fandom could look at those too and know they're gay for each other.) Difficult to explain to people outside the fandom.
You know the doctor and most of the companions will have endings that make you want to stab yourself in the neck to end your pain but every once in a while you get an awesome episode where everyone lives. You're willing to go through millions of feels episodes to get to the awesome ones. (Though the feels ones are awesome too but you're kinda too busy crying to notice). Lots of opinions on who's the best this or that. Never apply logic to who. Difficult to explain to people outside the fandom.
You most likely grew up with Harry Potter. The first movies might be a little scary but they end happily, but as it progresses it gets darker and darker and even though you know it's coming if its the second time around you get punched in the face with feels at the end when people die and at the very end when you realize that it's over (until you watch/read it again). But you keep going because you feel an obligation to stick with Harry until the very end. Most likely has the most fanfiction that excludes shipping and is basically 'everyone lives AU'. It would be doctor who, but the timeline is too...wibbly. For a while the fandom seemed dead, but them we got news of a new movie written directly by JK Rowling. The fandom likes sorting people into houses, and multifandom people sort characters from other things. Difficult to explain to people outside the fandom. (Which includes very few people.)
The weirdest combination of feels and hilarity. Progressively gets funnier and sadder as time goes on. It's hard to determine whether the feels or hilarity outweigh one another. Lots of people die, especially the ones we like. Somehow the power of the fandom brings lots of people back to life. They can accomplish almost anything. They have a gif for everything. Lots of people say 'that can't be a real line from the show!!!' it is. Many people are mistaken for satanists when they talk about it in public. Difficult to explain to people outside the fandom.
The Hunger Games:
It's sad. Realistic, but sad. Good for people who like adventure, dystopian worlds, and slow torture. Make it about the love triangle and someone will hurt you saying 'its not about gale or peeta!' even though most of the fandom is split perfectly down the line of peeta or gale. This fandom kinda stays in the background. Watching. Judging. Like Primrose's cat Buttercup, some wonder how they're alive, especially after Mockingjay. Difficult to explain to people outside the fandom.
You have sad back stories, I'll admit, but it almost always ends in happiness. The bad things almost always ends up happening only to bad guys. Of course, they sometimes make us like the bad guy more than the protagonist. Still, lots of sarcasm and hot guys. The fandom is good at analyzation, and uses it to rip everyone else's hearts out, but they make good memes. We aren't sure it was the fandoms doing entirely, but Phil Coulson was resurrected. Stick around for the extra credit scene. And the extra extra credit scene. Difficult to explain to people outside the fandom.
Divergent, The Mortal Instruments, & Beautiful Creatures:
Newer to the fandoms, but just as crazy, no doubt. They all have plot twists (though some of them were pretty predictable). Like most book series, they get more painful as time goes on. They have similarities with other fandoms, but they are their own works. Say they are the new _______ and you will probably be slapped. They use lots of odd words that make it difficult to explain to people outside the fandoms.
Similar to supernatural, but more pain and less hilarity. But, hey, what else do you expect from BBC? They cancelled the series on Christmas, and everyone's upset about it. Rightfully so. Difficult to explain to people outside the fandom.
Very polite fandom. If you are impolite to them they will kill and eat you. In love with the Merlin fandom. Subtle cannibalistic jokes. Difficult to explain to people outside the fandom with out seeming like a canabalistic serial killer.
Impossible to explain to people outside the fandom.
Countries personified to be humans. The fandom is in love with the Homestuck fandom. Not too difficult to explain to people outside the fandom.
The best torture you will ever experience. Our author is a bit...weird. He and his brother do youtube vlogs. Difficult to explain to people outside the fandom.
Lots of people hate the show, even people in the fandom. The show can be sad, but it brings up like every issue in the history of ever. Lots of singing. Difficult to explain the fandom as a whole to people outside the fandom.
Fairly normal fandom, but they like slightly abnormal people. Involves a lot of shipping Youtubers together or with some random fangirl/fanboy who is so totally in love with them. Difficult to explain to people outside the fandom, or people inside the fandom who doesn't follow that Youtubers twitter, tumblr, Facebook, and every other random site they may be on. People miss a lot of inside jokes when they aren't completely stalking that person.
You might think its stupid to group them together, but there are so many complex ones that I'll just say this. It can range from high school dramas to weird scientific fantasies to gory horrors to fantastic adventures or you could have one that bands all of that together into one big thing. Usually has a lot of pain and shipping. Difficult to explain to someone outside the fandom who hasn't read the book and watched the anime as well.
Dramas (like the kind they show late nights on ABC):
Mostly just shipping, but the dramas get complicated quickly, mostly because people leave the show for whatever reason and later come back and want to be in it again and have to be dramatically written out and later back in. The show could have almost any other genre, but it's full if things you don't see coming, and can make small things easily into big things. Lots of pain. (See Switched at Birth and Once Upon a Time for examples of Dramas.) Difficult to explain to people outside the fandoms.
Actually pretty funny, lots of music, and only slight feels. Always worth it. Great for singalongs. Lots of weird jokes. Difficult to explain to people out side the fandom.
Welcome to Night Vale:
Difficult to explain to people in the fandom.
Game of Thrones:
The things above sound painful? Lol. Not even sure why someone would join this fandom, unless they really hate themselves. Difficult to explain to people outside the fandom.
They live with knowing that everyone hates Twilight, especially the people in Twilight.
Marianne slumped against Pare’s vacant desk, the key to Bogach
tucked snugly in the waist of her boxers. Her eyes strayed to the clock
on the wall and she noted that it was half past eleven. Funny, she
hadn’t thought it had been that late when she ran from the inn. But
hey, what did she know about reality?