Cats' response to moving objects

I think one possible answer could be since the cats are inclined towards being a predator, it could be 'predator instinct'. Many cats like lions, tigers, leopards,etc pay attention towards moving objects and tend to run towards it

There is a saying, 'curiosity killed the cat'- it doesnt say anything about dog!

Another possibility is caution. Caution against possible dangers, that is why we see a cat's hairs stand erect whenever it sees a stranger.

i think its curiosity and its there with all animals. My little daughter who is 10mnths does the same. Any moving object catches her fancy and she tries a to grab it, play with it and then put it in her mouth

I agree with Swetha, it is the 'predator instinct' that is seen predominantly amongst animals of the feline family which is the cats. It is this instinct that makes them inspect and observe each moving object. This is also the reason that gave rise to the saying 'as curious as a cat'. We see this so much more in the kittens who run after even a piece of string, play with yarn balls and climb curtains, actions which make them so endearing and adorable.

Cat family is predominantly predators and that keeps them alert for prospective prey. A moving object let's them to be curious about it or may be a presumed prey. Moreover I have heard that cats are always on their toe or cautious of any danger

I would think it is a both irritation in few cases and enjoyment in few cases.