My Basset Hound, Fred, loves to see people coming his way that are wearing black pants. I really think he knows they are black. I think he sees only black. Maybe even smell black. When he sees black pants, he gets closer and closer to his prey until they bend down. "Oh, what a cute dog." Cute dog. He is 80 pounds. A bit overweight for his size, but fat and happy as I say. Anyway. Bending ever so close, he gets 'em! Slobber everywhere. All over those black pants. White, gooey slobber. Shoestring slobber. "I'm sorry, he really is attracted to black pants," I say. "Oh don't worry about, I LOVE dogs," they say back, with a grimmace on their faces. Then they actually see it, and say "Ooooo, ick."
Oh, and did I mention, he really, really loves when they are dry clean only.