In my first job I had a coworker that always was teasing me. Once I got really angry at him. I went to his desk and loosened (not simply disconnected) his keybo

In my first job I had a coworker that always was teasing me. Once I got really angry at him. I went to his desk and loosened (not simply disconnected) his keyboard plug, while talking to him. Rest of people noticed what I was doing, but not him. He could type for a while after I was back to my desk and before the keyboard went dead and he started to curse about a quarter of an hour of work lost. Everybody was laughing out loud, and louder because he was seeing that I had something to do with it but he can't figure out what.