If something like that happened, I'd think there was something severely wrong with my eyes. i think a lot of peopel would simply pretend nothing had happened, because they'd be afraid of the reactions of others.

But I'd like if some of the colors changed. Like if the sidewalks suddenly turned rainbow or something, the world would be a lot prettier.

There actually is a sensory disorder where black and white turns into vivid colors, I forget what it's called, but you can also taste shapes.