With the Opposite Sex
1. Bring them into the public eye, and immediately trash every little thing about them. Make sure they get a reputation as a rapist/slut or a homosexual (that is to say, if they do not wish to be a homosexual, not saying that being one is a bad thing). Make sure that they don't get dates, that at school or at work, they are frowned upon and named as your town's "black sheep." Don't just hate them. Make a point of it.
2. Doing number 1 just isn't enough. You then have to confuse the person even more by taking them behind close doors and hitting on them. Invade their personal space by touching them in ways that leaves him/her uncomfortable. Don't tell this person you like them. Just flirt with them. Ad nauseum. But not around other people. Only when you're completely alone. Otherwise, this plan won't work.
3. Continue treating said person like shit aside from ceasless flirtations. Try to become worse around other people. Steal things. Get the person fired (if you are working, if not, get the person expelled from school).
4. Start going to the victim's home. Try to seduce them (major plus if they aren't single, although they really should be if you've been doing what I said). Confide your secret love to him/her and have meaningless sex (remember, you aren't really in love with this person).Tell him/her that you can't let your relationship be seen by the public and that the two of you must not be seen together. You leave them in the act of silence.
5. In the meantime, whenever you are with mixed company and your spcial victim is in the crowd, hit on other people of the opposite sex. Make your victim feel lousy. But right as you think they're going to walk away, turn towards them and wink.
6. Stop having sex with partner. Instead, request oral sex all the time. Take everything to your advantage. Borrow money off of him/her, large amounts. Take their car and go on dates with other people in it. Have sex with other people in it. Make sure it smells strongly of the date's fragrance or has cum stains on the seats when you return it.
7. Tell the person you love him/her with all your heart, but when they tell you, change the subject. Don't ever let them speak their mind. It's all about you.
8. Let a few people find out about the two of you. When asked, grip your arm around your victim's shoulder and say, "Nope-we're JUST friends." in a smug, confident tone. When they ask you about this, tell them that you didn't really think your relationship was anything higher than a friends status. That you love him/her too much to jeapordize your friendship. Meanwhile, continue fucking them. Assure him/her that this is strictly platonic.
9. This is obviously going to bring a few tears to their eyes. When you see them crying, take pictures. Post these at work/school. Get people involved in their "depression." Make sure your victim ends up in a mental institue.
10. Once they get out, explain to them that you have decided to start dating your ex-girl/boy-friend again and that you can stop loving each other now. Refuse to touch the person. Slowly leave them out of your life. When they call, loudly proclaim that you're on the other line with your girl/boy-friend. Act giddy. Start telling them every little thing about your relationship. Talk about hot guys/girls you saw today. Continue doing this to them for as long as you know them.
11. Announce that you will be moving half-way across the country, but will see them again. Move, but only write them to declare that you never loved them. That it was a huge joke set up by your friends and that you hate them and always have.
This will make anyone miserable, paranoid, and emotionally scarred for life. I know some of this because it's happened to me... specifically numbers 8 and 11. Of course, if you really had any mind to carry this out completely, you'd be not only ruining someone else's life, but your own as well. Only one badass mofo could carry something like this out.
By the way, I am not insinuating that all guys are jerks, if that's how it appears. For every bastard who wants to break a girl apart, I know one who wants to break that bastard apart.