Feline Minds
Cats have a completely different outlook on life than we do. Cats see more with their noses than they do with their eyes. The world is one of smell and sound, not color.
Smell-O-Vision
That world of smell explains a few odd things about cats. Sometimes when you take a cat to the vet, yet leave its companion cat at home, the one who stayed home doesn't recognize the one who went. The cat who went to the vet is covered in antiseptic smells, and does not smell like it did when it left, so to the cat who stayed home it is a different cat.
Cats also often want to sniff someones hand before allowing him or her to pet it. My cat especially does this when I've been near another cat, or a dog recently. Some may even decide that they don't like how you smell, so will not let you pet them.
