The opposite top/bottom dynamic for my OTPs to the one I like. I would have a bunch more fics to read if I enjoy all configurations, but I just can't get into it. Occasionally I'll come across a fic where I genuinely can't tell who'll top and who'll bottom until I get to the sex scene(s), in which case I'm usually fine to keep reading. But 98% of the time I can guess top/bottom roles by how the characters are written, and if it's not my preferred configuration then I'm out.