The Mistborn Trilogy by Brandon Sanderson. Very solid start, decent enough second and third book... and then the ending resolves everything on a really ridiculous bit of semantics that's kind of implicitly transphobic. BLEH.
Sanderson's early stuff really struggled with endings in general, just A Lot Happening Very Fast. I'm glad he mostly broke those habits by Way of Kings, which I think has one of my favorite endings ever, because Warbreaker and Elantris are also victims of the Sanderlanch.
My personal vote goes to the K-Drama 'Black'. It is SO MUCH BETTER if you just don't watch the last half hour. The back end of the final episode seems driven to beat by beat undermine the entire story.
