Quote Originally Posted by cloves
kittens do the "kneading thing" when they nurse too don't they? I had heard it was some sort of throwback to their kitten days, that when a cat felt most comfortable it was just instinct to do that behavior.
You are correct, nursing kittens do knead.

Actually, kneading is a better indication of a cat's comfort level than purring, as stressed cats will often purr up a storm.

This silver ball of fur on my desk is snoring at present, which seems to be her expression of maximum comfort.