Something I'd never needed to think about before:
Why do you get cats with contrasting white extremeties(paws & tail tips & chests) but never black or other colours?

",,,Humans probably also selected for cats who were calm and comfortable around humans, Lyons* said. Behavioral traits seem unrelated to coat color, but for reasons that scientists don't fully understand, white spots tend to appear when the tamest individuals are selected and bred. It's true of horses, pigs, mice, cows and rats.

These distinctive fur colors and markings emerge while a cat embryo is developing. The cells that give cat fur its color first appear as neural crest cells, which are located along what will become the back, Lyons said.

Then, those cells slowly migrate down and around the body. If those waves of cells move far enough to meet each other on the cat's front side, the embryo will be born a solid-colored kitten, such as an all-black or all-orange cat. Felines develop white feet, faces, chests and bellies when these cells don't quite make it all the way."

*nice bit of nominative determinism ;)
Leslie Lyons, professor emerita and head of the Feline Genetics Laboratory at the University of Missouri College of Veterinary Medicine.

more
www.livescience.com/why-cats-have-white-socks-on-paws.html

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All because somebody on Facebook was looking for a replacement cuddly toy tabby cat which had to have black paws.