From back of the 5th Edition rules:
Paranoia is a rolepaying game set in a darkly humorous future. In Paranoia, a well-meaning but deranged computer desperately protects the citizens of an underground warren from all sorts of real and imagined enemies.
You play one of the Computer's elite agents. You job is to search out and destroy the enemies of the Computer. Your worst fear is that the Computer will discover that you are one of these enemies.
Paranoia: a lighthearted game of terror, death, bureaucracies, mad scientists, mutants, dangerous weapons, and insane robots, which encourages players to lie to, cheat, and backstab each other at every turn.
Is that fun?