I get pissed off at even the smallest things regarding spoilers. In the case of FF7 I had first bought the game and just went looking for random websites about it. I then read that Cait Sith was in reality a Shin-ra spy just after I got him in my party. I was really angry at knowing this spoiler and then never read anything more online about it until I beat the game.

I did the same thing with FFIX, and the experience was alot better because of it.