Personally, I find a sick kind of enjoyment in knowing things that other people don't/can't.
I guess, though, that while I would be upset if I was expecting something to be in the game which didn't make it, but I do find it interesting in retrospect to know what could have been. For instance, did you know that an early incarnation of Abe's Oddysee had Abe as a monk and Molluck as the leader of a sinister cult - well, something like that. Or that jumping could very well have been left out of Munch's Oddysee?