Some people at Car shows

Then theres the ones that don't even need to see your car to make judgements. I remember a friend going to the DMV to register a 68 Dart he just bought. The clerk could barely speak english, but knew enough to say, "Oh, thats one of those ugly green cars isn't it?"
I remember telling a girl that I drove a 68 Plymouth, and she recalled an ex-boyfriend of hers who had an "ugly green Duster".
Why is it that our cars have the reputation of all having been painted an "ugly green" color?