I will oblige and say "romance".

Though honestly, I prefer romance with speculative elements, or at least strong historical worldbuilding. Similarly, I don't mind a mystery with strong spec elements (and a nice romance element) but I don't know if "I like these genres in speculative fiction" counts properly as "what non-speculative genre do you like?"

There are two categories of books reference and fiction. Prove me wrong.
I mean, you're not wrong, but it's also not helpful for finding more of the thing that you like to read.