What's the normal method for getting a character to hate you? Why would you? I like to cheat my energy so i end up using small talk/compliment/flirt a lot and naturally end up with a decent amount of love.
edit: who has hate path stuff?
When you have Nora's research questionnaires unlocked, if you get Gabrielle below -25 love (and maybe have Obedience or Sluttiness over a certain number, I don't remember), then you can study her to get the serum trait Cousinly Hate, which gives +1 Sluttiness/Day per 5 Love below 0. If you get her (or anyone else, but you might as well stick with her if you've already got her that far) below -50 Love, and then study her again, you get serum trait Distilled Disgust, which instantly reduces the serum-taker's love by 50. So if you used both of those on someone who started at 0 love, you could get a Sluttiness increase of +10 per day (presumably, I haven't tried it myself).
The main thing I did to get Gabrielle down below -50 was hiring her, and then Insult Her Work every day (-2 each time). I think blackmailing her reduces love too, but you can't do that as often. Off the top of my head, you might also be able to get -Love by groping someone who's not into it, or ordering them to strip when they don't want to. Whether those result in penalties will probably depend on stuff like Sluttiness or Obedience.
I'm not aware of any benefit to doing it outside of giving them a serum with Cousinly Hate, or any other scripted characters with a hate path. But this game is a sandbox, so maybe it's just there for people who want to play it that way, because they have a kink for hate-fucking or whatever.