Imagine a world where colors are the most important thing in your life. Not because you need them to put together a matching outfit, or know that a red sign means stop, but because you use them to literally read the people in your life.
Scared people are green, hungry people are greyish-blue, warm and kind people give off an orange light. People who are a threat to you are blue. Everything else in your world, most of the time, has no color at all. Color tells you everything that matters, but the real colors of things can no longer be seen.
You can't enjoy a sunset, but you know when your best friend is sad and isn't telling you. You can't take in the color of a field of flowers, but you can tell the natures of people you've never met. You can avoid a sleezy jerk at a club, because you know his intentions. But someone else will have to dress you because you have no idea what the color of the dress you're wearing is.
Is it a good trade? Is that a trade any of you would make?