Three dollars and some change

That's exactly what I've been trying to explain to my friends who find fanfic weird and scary and full of squicky pairings: you need to read the good stuff.

To paraphrase somebody-or-other, 90% of everything is crap. For instance, I know that there are some really dire novels out there on the shelves, but by luck or judgement I've avoided most of them (every so often I find myself reading one bad enough to assure me that I don't, actually, just love everything I read). It's the same thing for fanfic, only multiplied about a thousandfold.

Give me solid characterisation and pacing and a good dialogue/description balance, and an actual plot, and I don't really care what pairings (if any) the author has in there. Like you said, the author must make me believe.

And you're doing just fine on that front :).