Some people enjoy practical jokes. These are the people on whom it is acceptable to PLAY practical jokes. The only people.
These jokes are inherently cruel. They inflict suffering on the butt of the joke, whether that suffering is in the form of fear, injury, embarrassment, damage to property, or simply wasted time. If the victim doesn't appreciate the art of the practical joke, then there is never any excuse to subject him or her to this suffering.
If you want someone to "loosen up," get to know them. If you want some attention from that cute biped, try flowers. If you want vengeance... well, you might be better off seeing a therapist.
