Honestly? When dealing with females, the term "I hate you", can alot of the time mean "I Love You". Sounds complicated, but who said love was simple???

The act of hating you.

i have extremely strong dislike for you.
you are a twat, idiot, cunt, imbecile, loser, moron, bitch, bastard, really horrible person, retard, knob (insert many more insulting words)

The fundamental opposite of I Love You. Though this can be used without necessarily feeling the lack of love for an individual, usage within a relationship can and will cause the counterpart to instantly lose all interest in you instantly.

Usage outside a relationship, however, can have some positive effects. For instance, an annoying individual who hangs around you against your choice could be the receiving end of "I Hate You", and then likely find another individual to bother.

In the world of metal, using the term " I hate you" actually is a way of saying "I love you". As was previously mentioned, metal'ers are not allowed to love, so they show said emotion through acts of hate.

what you say to someone when you're too scared to tell them you actually love them! you try to cover up your feelings by pretending you feel the opposite to love...