How does Neverwinter Nights decide my Neutral Good character can’t use a Lawful Evil sword? I have no idea, and every work of fiction that tries to explain it turns into either tragedy (Goblins: Life Through Their Eyes) or farce (The Order of the Stick.) YMMV which way this prompt would go.

(There’s also Fable, where the simplest way to convince an evil gate to let you pass is to collect twelve live baby chicks and eat them raw in front of it.)