Dammit... I like it all!

For me, it’s Anne Rice’s The Vampire Chronicles. There was a lot to love in those first novels and even as it lingered it had bursts of interesting developments. And then it got so, so, so bad, both due IMO to inadequate editing and just terrible vision. I made it to Blackwood Farm before my rage forced me to say…

WoT is the obvious answer of course but I would say a lot of epic fantasy falls into that trap. ASOIAF too

“Wheel of Time” by Robert Jordan/Brandon Sanderson. The series probably needed to be about 6 books shorter. There were whole books- long books- where it felt like NOTHING happened.