> I dislike the polymorphism one, simply because it is so closely tied to most OO languages and inheritance that most people–when overriding or overloading a method, for instance–use it without ever thinking “oh! this is polymorphism in action!”

This comment is a perfect representation of why "the polymorphism one"is, in fact, a good question. OP immediately (and apparently exclusively) associated polymorphism with subtype polymorphism (and inheritance in particular), while ignoring other types of polymorphism.