The condition that many sequels to successful films suffer from: re-hashing of plot points, shoving the best parts of the original back in your face until you almost hate it, ETC, all while trying to make the movie "bigger and better" than the original through the addition of an over-abundance of special effects, or new characters that you just dont care about (or, on some occasions, omitting major characters that people DID care about). Sequelitis can make one of 2 things happen: the third film will back off and be much better than the second, or part 2 will have been so awful that a 3rd never even gets made.
I dont remember there being a "Men in Black 2" until I saw it the other day, and now I remember why I forgot it to begin with. "Lets take a small joke and turn it into a main character!" Totally suffers from sequelitis.
A spiritual sequel, sometimes called a spiritual successor, is a successor to a video game, movie, novel, comic, stage play, or television mini-series. Instead of being a standard sequel, spiritual successors share genres, themes, styles, and often developer teams, without continuing on a previous story. While this term can apply to almost any content, it has most commonly been used in video games.
A person who cannot wait for the next installment of their favorite movie to have one last adventure with the characters. Lately this has also branched out to video games and TV shows when no direct movie sequel can be created.
A painful condition that affects winners of reality TV shows past the first season, consisting of not being able to accomplish success of any degree. See American Idol winners, America's Next Top Model, Apprentice, etc.
Person 1: Ouch, Lee DeWyze's debut album only sold 141,000 copies.
Person 2: Sounds like a bad case of Sequential Season Syndrome.