As was already said, black dogs are very common and a lot of people just find them boring to look at. Black dogs also tend to scare people more easily for some reason. I like black dogs and besides certain reds (like Tollers) and chocolate, black is my favourite colour (with or without markings). I think the colour of a dog is a rediculous reason reason to get rid of it though. Eventhough my favourite coat colours are reds and browns, I wouldn't get rid of a dog because it was white or black.