All the time.
My friend keeps on telling me to watch the Bleech anime, and I would be more than happy to do so, at least if it wasn't 366 episodes and 4 movies long. At that point, it is no longer a TV show, it is a goddamn commitment. I'm sure that it is a great series, but I can guarantee you that a fair amount of those episodes are useless plots, filler episodes and at least one beach episode. If someone could say to me: "Hey, if you watched episodes X, Y and Z, that is pretty much all of the important stuff and you wont miss out on anything" then I might consider it, but 366 episodes and 4 movies*? Fuck. That. Noise.
Same goes for games. You can have the best combat system at the time, or a huge open world with a lot to explore, but after a while, I will just get bored. Enter: Batman Arkham ________. I love the Arkham series, but my god does it get boring after a while. When you first start playing the game, it seems like it is the best and most fluid combat system that I have ever played with, but after you punch the 3000th goon in the face, you soon realise that the combat never changes one bit, but only gets easier. Same goes for WoW. I love my level 100 Hunter, but I wouldn't be lying if I said that even at level 100, I use about 6 abilities in combat consistently. Six. I can tell you right now that it is getting only slightly boring.
[small]* 4 movies run time = 380 minutes. 366 episodes that I am assuming are around (on average) 22 minutes long each = 8052 minutes. 8052+380. You would be looking at around 140 hours. That is more time than I spent playing the entirety of Dragon Age: Origins (+DLC) and Dragon Age 2 (+DLC) combined.[/small]