When a predator kills prey it feels good to the predator because it usually means they get something to eat. Killing a mouse, for example, feels good to a cat. It has been shown that the brain circuits for predatory killing come from “essentially the same brain areas” as the “searching” circuit, which produces pleasurable feelings of curiosity and anticipation.
When the “searching” circuit is turned on, animals (and people) seek the things they need such as food and shelter. People and animals love the hunt. Spend some time playing with a cat using a laser pointer. Cats can get carried away chasing and pouncing on a red laser dot. They are truly enjoying the hunt. Cats then go into hyper-activation of the predatory chasing instinct and are so fixated they could have injured themselves.
Cats can see the dot but can’t ever catch it. The laser dot probably becomes a stimulus that doesn’t turn off because the cat can’t complete the final catch, so the chase instinct is in a perpetual loop.
It’s somewhat strange that the way a cat will attack a laser pointer is not the way a cat will behave outside chasing live prey.
Some cats will not chase laser pointers, but why? Cats raised inside are more likely to become hyper-focused while chasing a laser pointer dot. Cats raised outside learn what is good to chase and when to chase it. They learn to control their chasing instinct so they can stalk prey and get close enough to catch it. An outdoor cat that has learned to hunt actual food may not be interested in a laser dot. For one, a laser dot is not food and cats have made the connection between chasing and eating. Also, cats know how to suppress their chasing instinct. They aren’t seduced by the rapid motion the way domestic cats are. Nevertheless, the fact that some cats don’t chase laser pointers while others chase frantically may prove that what an animal chases is learned, not instinctual.