What's the most annoying crime/thriller/mystery/romance/suspense trope?
It's hard to make a list, but I thought I would list one of my pet peeves. For me, it's the entire chapter devoted to the life of a character who happens to discover a dead body that our main character (cop, medical examiner, etc) is eventually tasked with solving their murder.
9 times out of 10, they discover the body, have an interview with the police, and are never heard from again. Except we get a whole chapter about what's happening in their life, how they feel about their current circumstances, and all sorts of other information about them that is completely useless - because they disappear from the rest of the book! Why is this being included? It's not necessary! I suspect the big reason is to boost the word count. Secondly, the author may want the reader to think that this character will become important later on down the road. But, as I've said, 90% of the time this is not the case, and we're left with 15-20 pages that contribute nothing to the plot.
I see it in nearly every crime book I read and it drives me nuts.