Hmm, I actually though Fathoms Five to be the worst transgressor in that regard. A girl called Arabella? Mulder and Scully and William in a house in California, with a pool? I didn't buy that. At least Parabiosis lifted the characters above canon, albeit in a highly idealized way. That said, I adore Contact High.

No, fic doesn't have to be like life, but the stories that move us most are those that you feel could happen in real life. I like Penumbra the way I like Michael Ondaatje's writing - utterly gorgeous, but completely fanciful.