Cats always have curious habits and behavior, and one odd behavior involves moving a water dish before drinking out of it. Most people just assume their cat must be mentally insane so any type of behavior won’t surprise them. However, there’s a reason for cats moving water dishes.
In the wild, cats expect moving water so water sitting in a dish may not look like drinkable water to them until it moves. That’s why cats may stick a paw in it and stare at the ripples. Another reason might be your cat is just crazy so no amount of scientific inquiry will ever explain why your cat does what it does.