I always end up spoiling the hell out of anything i play/watch/get involved with. I'm already well aware of everything that's happening in One Piece, even though i've currently paused viewing in the middle of the Thriller Bark arc, i've been picking away at the big plot twist in the middle of Tales of Symphonia (thus i'm well aware of what's coming in the Tower of Salvation), i completely killed every Fire Emblem game i've ever played, and i relentlessly spoiled Higurashi (murder mystery anime) for myself after getting a taste of it.
It generally doesn't bug me, as i've found that the journey is more fun than the destination. Just because i know that the Straw Hats are going to triumph over Gecko Moria, just because i knew that Ashera would end up being the final boss in Radiant Dawn, didn't make seeing those things any less awesome than it was.
Monster Hunter: pissing me off since 2010.