The Dark Tower/YMMV

• Anticlimax Boss - Randall Flagg who was killed by Mordred, Mordred who was at the brink of death and half crazy by the time he met Roland, and the Crimson King who was, for a long time, utterly insane. Also the Tick-Tock Man, brought out of the city of Lud by Randall Flagg to confront the gunslingers and then killed on sight by Eddie and Susannah.
• Canon Sue Aileen in the comics.
• Creator's Pet: Susannah is easily the most disliked character of the Ka-Tet, largely due to her annoying split personalities. She's also the only one other than Roland who gets an entire book dedicated to her, and the only one that gets an (arguably) happy ending
• Ending Fatigue - an alternate name for the trope could almost be "Dark Tower Syndrome".
• Esoteric Happy Ending: Susannah goes into an alternate reality version of New York where Eddie and Jake are still alive and in fact are brothers. She appears in Central Park at Christmas time, alternate-Eddie greets her with a cup of hot chocolate, and it's clearly supposed to be her happy ending....Except many readers feel that Susannah abandoned the quest and is now trapped in a world that isn't her own with a couple of Replacement Goldfish who aren't really the people she loved.
• Everyone Is Jesus in Purgatory - Mocked in The Dark Tower.
• Fridge Horror: The idea that Roland's constant recourse to ka throughout the previous books is not out of any genuine sense of destiny, but simply because he has trodden this same path so many times and on some level he remembers what's coming.
• Foe Yay: At the very least, The Gunslinger has a bit of suggestive subtext between Roland and The Man in Black towards the final chapter.
• Harsher in Hindsight: The Drawing of the Three has a scene where Roland (possessing Eddie's body) takes a plane into New York and ends up causing a panic when a stewardess hears him mutter a few words of the High Speech and thinks he's a foreign terrorist come to hijack the plane. This was written over a decade before 9/11.
  • Not quite; Arabic-speaking terrorists hijacking planes is Older Than They Think and has been going on for decades (not just Arabic-speaking terrorists mind, but they have done it often enough). 9 /11 was significant because prior to that said hijackers didn't resort to kamikaze tactics and were usually just out to force the plane to land at a location of their choice.
• Jumping the Shark - Some fans believe this happened with Wolves Of The Calla, which was written soon after King's car accident. Others cite Wizard and Glass, or even as early as The Drawing of the Three.
• Magnificent Bastard - The Man In Black, Marten, Randall Flagg, and Walter. Why, you ask? Because they are the same person.
• Moral Event Horizon - Roland leaving Jake for dead at the end of the first book solidified his status as an Anti-Hero.
  • To be fair, it doesn't stick forever, but the guilt for such an act sticks around for awhile, and the third book both subverts (in effect if not in morality) the MEH and reminds the readers and Roland about how depraved such an act was.
• Nightmare Fuel - The Charlie the Choo Choo book is an in-universe example; King definitely intends for his own readers to find it creepy.
• Replacement Scrappy: After being King's ubervillain since the 70s, King thought it was a good idea to replace Randall Flagg with the newly-introduced Mordred as Roland's main antagonist for the last book.
• Seasonal Rot
• Shoot the Shaggy Dog: Many fans felt this way about the ending.
• Squick - Rhea examining Susan in Wizard & Glass. Ew. In fact, Rhea in general.
• Surprisingly Improved Sequel (The Dark Tower, according to Stephen King.)
  • King even went back and republished The Gunslinger with some changes to bring it more in line with the rest of the series.
• Tear Jerker: Roland's reaction to Susannah's decision to leave.
  • Jake's deaths, and especially Oy's depression after the final one.
  • And Oy's death.
    • This line in particular:

The body was far smaller than the heart it had held.

• • Eddie Dean's death.
• Too Soon: The scene in Song of Susannah where Jake and Father Callahan travel to the year 1999 and leave Black Thirteen in a locker in the World Trade Center so it will be destroyed in the future could definitely qualify. Also, there's a scene in the last book that mentions that the Mid-worlders actually sell tickets to witness the 9/11 attacks.
• Villain Decay In the final book, Walter o'Dim/Randall Flagg and the Crimson King, the two main villains up until that point, are reduced to almost non-entities. In particular Flagg, who had once been considered King's 'ubervillain', is easily dispatched in one chapter by a newly introduced character.