Unrequited love that remains unrequited through to the end. I love either an author willing to stick a sad ending, or finding an alternative the narrative arc that ends happily but not with the main OTP getting together. I love thousands of words of horrendous internal suffering, desperate pining, great emotional pain, and then the person just...getting over it. Moving on. Learning how to cope. Growing up. Whatever.
Re: bulletproof kinks