Do you have a writing taboo? Is there something you wouldn’t include in a piece of fiction? Do you have reading taboos? Is there something in a book you hate to read?
Firstly, a definition:
Taboo (noun)
a social or religious custom prohibiting or restricting a particular practice or forbidding association with a particular person, place, or thing.
Taboo (adjective)
prohibited or restricted by social custom.