Ice crystal size and air quantity. Ice cream is constantly churned to keep crystal size as small as possible as it freezes, and well as to incorporate air into the mix, both of which make it creamy and more pleasant to eat.
Eww... I wouldn't do that. It separates and the fat and flavouring comes to the top while the water and everything else sinks to the bottom. I have two tubs in the freezer to throw out.
