For me for example its “Eat me - a natural and unnatural history of cannibalism” by Bill Schutt. Its an amazing book that covers cannibalism in animals and then the history of it in humans (cultural, survival & medicinal cannibalism).
I got a lot of “oh why would someone read something like that?” And “that not something fun to read about!” From relatives but my friends enjoyed the stuff that I could tell them about cannibalism!
One Summer: America 1927 by Bill Bryson is the same for me. I never would have picked up a book about one summer in United States history no matter how interesting it was supposed to be if I didn’t already love Bill Brysons writing. I’m so glad I did though it was amazing