Or romances where they've fallen in and out of love a whole bunch of times, and all the tensions that come with that! (I haven't seen this trope as much in books as I have in movies, shows, and musicals, but it's still a good one.)

Costis in general is such a great narrator. I love how his stolid, wonderful honorable-ness bounces of Gen's...everything; they have such a fantastic dynamic. I was ridiculously happy when he showed up again in Thick as Thieves.