Names
Names are important; without them we’d all be yelling “Hey you, in the green!” when we wanted to talk to someone, and everyone in green would think we were talking to them. It would be very confusing, not to mention loud. Maybe wearing something chartreuse would mitigate things, but only if others knew the difference between green and chartreuse. (Which in any event comes back to names, in this case the names of colors rather than people.)
Names can also be controversial. When word got out that my name was going to be an abbreviated form of a saint’s name, my mother got a letter from a nun announcing that she (my mother) simply couldn’t do that.