Déjà vu, a feeling of intense familiarity with a situation that is brand new to you, has an opposite feeling: jamais vu—an unsettling and eerie feeling that something which should be familiar to you is not. Jamais vu is often experienced by people with amnesia and other memory-related conditions.

Night vision goggle displays are green simply because the human eye is capable of distinguishing more shades of green than any other color.