Definition: Falling so far behind on a tv show that the series ends up turning crappy and all your friends are making fun of it, so you're now no longer motivated to catch up.
Examples: Homeland, Dexter, Weeds, 24, Sons of Anarchy
Definition: Loudly and selfconsciously declaring your ironic love of something that's actually just good anyway and everyone already likes it. Also, relax! You're allowed to just, like stuff.
Examples: Hall & Oates, Journey, The Bee Gees, Elton John & Billy Joel, Any Cheesy Late-80s/Early-90s Hip-Hop Song, Pretty Much Any Current Top-40 Hit Song
Definition: When a movie has achieved a state of notoriety where it's been parodied so many times, that now when you go back and watch the original, that almost seems like a joke. ("Make him an offer he can't refuse?" "Luca Brasi sleeps with the fishes??" Could this be any more derivative?? Oh wait, this movie literally started all these cliches. STILL THOUGH...)
Examples: The Godfather, The Wizard Of Oz, Casablanca, The Matrix, Star Wars, Forrest Gump, Anthony Hopkins in Silence of the Lambs, Bob Dylan's voice
Definition: When an artist releases one seminal work then follows it up with an entire career that never lives up to it, and every time you keep thinking "mayyyybe this next one'll be good...? Please?"
Examples: Meat Loaf, M. Night Shyamalan, Frank Darabont, Weezer (two great albums, but still counts), Rod Stewart, Every Supporting Actor In The Sopranos
Definition: A movie that used the cutting-edge technology of the day but now looks really specifically dated to that exact timeperiod, thus ironically making it look much older than a lot of actually-older movies.
Definition: Getting really defensive about how much better kids' shows were when you were a child than they are now, even though the stuff you liked as a kid was clearly just as stupid and if you went back and re-watched it you'd be embarrassed.
Examples: Depending on your age...He-Man, G.I. Joe, Ninja Turtles, Power Rangers, Inspector Gadget, Captain Planet, every toy and cereal commercial that worked on you, you name it. Basically anything but the Nicktoons.
Definition: When an actor or musician's crazy personal life causes you to judge their work more harshly, even though the work itself is exactly the same as it always was.
Examples: Tom Cruise, Mel Gibson, Lindsay Lohan, Chris Brown, Michael Richards, Shia LaBeouf, and the best example ever, Katie Holmes in Batman Begins (no one would've noticed/cared about her performance if it were any other actress doing the exact same thing)
COROLLARY: This can sometimes work to the artists' advantage, when it allows people to be like "Say what you want about [Kanye West / whoever] as a person, but that new [album/movie] is awesome."
Definition: When a show clearly blows its entire special effects budget on one episode, so you know nothing super-crazy is gonna happen for at least the next five episodes. Bring on the dialogue!
Examples: Battlestar Galactica, Game of Thrones, Lost, Boardwalk Empire
Definition: When a character on a tv show gets a new job, gets into college, or any other stroke of good fortune that, ironically, takes their character out of the world of the show, thus leaving the actor out of work. (When Jason Street on Friday Night Lights finally gets a job as an agent in New York, everyone celebrates and is super happy for him, then all it actually means in real life is that the character disappears)
Examples: Jason Street on Friday Night Lights, Gwen from Season 1 of Downton Abbey, Karen on The Office, Any character who's ever gotten into college and had a tearful goodbye
Definition: When a tv show has a character who's a huge asshole but that person becomes a breakout hit character, so in subsequent seasons they have to make their dickishness a little less total and give them more 'nice' moments.
Examples: Ari on Entourage, The Dowager Countess on Downton Abbey, Daryl on The Walking Dead (ended up not being a dick at all, after seeming like he's start out as Merle's bigotty brother), Kenny Powers on Eastbound and Down
Other examples? Leave 'em in the comments!