Nothing is more satisfying than seeing your peer be overwhelmed with shock and awe, fear, or temporary anxiety. If you like to screw around with other people's belongings, especially computers, then try these three ways to troll in real life.
1. Insert Key/International Keyboard
Not many people know about how the insert key works (at least on non Mac PCs). If you press it, every time you type something, the next characters are overwritten. If you're in college and your roomate is trying to type up a research paper, nothing is more annoying than that blasted "bug" where you can't edit anything without overwriting what you already wrote. Go ahead, give it a try. It's really annoying, isn't it? Better yet, set up an international keyboard, so when he/she tries to use quotation marks, it won't do anything the first attempt, and on the second attempt two quotes will be returned. Very annoying when trying to cite a quote.
2. Scary Maze Game
I'm not sure if you've heard of this game before, but it is more or less a way to scare the living crap out of an unsuspecting person. The pretense is that the game should be difficult, as it requires high concentration to get out of the maze. You control a dot and must guide it to the end of the maze without touching the corridors. The player can beat two levels without anything popping up yet, so it conditions the player to expect the same things to happen on the third level. The third level is much more narrow than the previous ones, which requires even more attention. This is the highlight of the prank: once the player nearly reaches the end of the third level, an eardrum-melting, shart-inducing screams will be blasted through your speakers, accompanied by a flashing, seizure-inducing sequences of gruesome face of the original "Exorcism girl". At this point, the user typically has a hysterical reaction, which is always fun to see.
3. Install "Embarassware"
I'm not even sure if embarassware is even a meme word, but there are programs that can really embarass you. For example, if you're studying with your friend at the library, you could easily install a program that halts the shutdown process and plays super loud porn sounds. I saw a YouTube video of a guy doing it to his friend once, and a bunch of people in the library looked at him with annoyance and disgust while I laughed my ass off. Another one is picking a lame ass song, high pitched frequency noises, and animal sounds. Playing shitty screamo or noises that want to make you throw up are great ways to pull this off.