You just ABSOLUTELY HATE someone you know in real life? Well one thing you can do is plant evidence on them of a crime. One example is:
Take a cardboard toilet paper roll or paper-towel roll, an then put duct tape on the ends so it looks completely sealed even on the ends. Then paint the whole thing red (it'll look like stereotypical generic dynamite like most people are expecting to see when they see dynamite). Then make several more the same way. After the paint has dried, Duct tape them together to look like a bundle of dynamite. Also while the paint was drying, you should be doing this next step. Open a calculator, alarm clock, etc and find some circuit boards. Remove these boards. After that, strap one or more of these boards to the the fake dynamite bundle. Then when your enemy is you so despise is going to fly on an airplane, before he leaves for the airport (and while he's not home like on last minute errands) pick the lock on his house, then the lock on his suitcase, and put this fake bomb inside, then lock everything back up.
Remember, when doing all this stuff listed in the above paragraph, ALWAYS WEAR RUBBER GLOVES SO YOUR FINGERPRINTS DON'T END UP ON ANYTHING.
When he gets to the airport, the luggage scanner will find the fake bomb. TSA is gonna think it's real. And now FBI, CIA, ATF, DHS, etc will show up and arrest the guy. Since the charge is terrorism, he'll be treated as a terrorist. He'll be sent to Guantanamo prison for the rest of his life without a trial.
Because there was no trial, the evidence won't get examined, including evidence that would show his finger prints weren't on it, and that the bomb was in fact fake. Both of which would get him acquitted of terrorism charges. Thus the terrorism charges (without any possible refutation or even any process by which they could be refuted) will STICK! And he'll be locked away for life in Guantanamo!
What an EPIC END for whoever happened to be your enemy!