Well when there is a game/movie/book that is well told and especially when it's very self contained, it does "irk" me when a bad sequel, or prequel comes out trying to continue on from a story and consequently either not living up to expectations, or just over exposing the last one.
Although this is probably why I don't mind, (in fact recently I've come to love) reboots, since like a good sequel, they don't attempt to trample on the legacy of the old. Reboots to me, just give a "what if" scenario. Hell, even if a sequel or reboot isn't good, I just don't buy it, that's all there is to it.
That being said, if there was a series I really would prefer not to continue, it would the Silent Hill films. Not because I'm screaming betrayal or any nonsense, but rather that they just don't work in film. There is no way you can transfer the atmosphere and sense of dread from a horror game to a horror film. In a game I am a participant of the horror, in a film, I am the witness to the horror, it's just not the same sensation.