So what color is the dress?  Gold and white?  Black and blue?  As Josef Albers could tell you, the answer is entirely subjective.  It depends on which colors are next to each other.  Don’t believe me?  Check this out.  The brown squares are the same color.  Or this example from XKCD.  Go ahead, check out the color values for the dress colors with an eye dropper – they’re the same!  Color is amazing, and if you want to see more, there’s always the Josef Albers iPad app.