I agree it's an odd comparison (2+ hour movie versus 6 episode season of a TV show where each episode might be in the 2 hour range), but for me it's Game of Thrones and it's not.
And it's not because I LOVE LOVE LOVE Game of Thrones (I like it fine, but I'm not a fanatic). Rather, it's because all of the superhero movies of the last 10+ years started boring the crap out of me at least 3-4 years ago. I looked at the Wikipedia list of Marvel movies (starting with the first Iron Man in 2008). I think I saw all of the "Phase One" movies except for The Incredible Hulk, and I think I saw all of the "Phase Two" movies except for Thor: The Dark World (not sure about Captain America: The Winter Soldier). I actually enjoyed Ant Man, but at that point I was basically done, and pretty much none of them were tolerable after the first iteration. I saw Black Panther at home on demand and thought it was ridiculously overrated. And the recent DC movies (starting with Batman Begins) are generally all even worse, although I haven't seen as many of them.