Lack of knowledge about the show, which meant I wasn't actually repelled by reading fic based in it (unlike some equally productive fandoms) + the fact that there's a shedload of fic out there and it was at a time when I was basically only reading SG-1 (I think) and that fandom was small and I'd pretty much tapped it out.

I'm not much of one for crossovers, mostly because in my experience the writer knows one of the fandoms way better than the other and it's unbalanced, so I couldn't be led astray that way anything like as easily...