They are often a purely instinctual animal. So if your hand is on their belly, let us say, they cannot move and are vulnerable to attack on their backs so their first instinct is attack your hand.
But it is not just the mutual respect that I have for each animal, it is the level at which I wish I could understand them that makes me love them so much. Another big reason why I have always loved animals more than more humans is because unlike humans, who go rogue and traverse down their own paths and ways if thinking, animals are all purely instinct. They react and base their decisions mostly on what evolution has told them to do over many, many years. They are such intelligent creatures as well. On a more personal level, my cat Jensen, has learned overtime by watching us, how to open cabinets and doors.
(My cat, Jensen)
But animals like Koko the gorilla, have managed to learn human communication in the form of sign language. There have been studies too, with animals such as dogs and cats that have shown these animals ability to detect early onset illnesses and diseases. Animals are such talented creatures too. Animals such as octopus can go completely invisible and a lot of animals such as pigs and elephants understand how to paint and once again, are some of the smartest creatures on earth.
(Koko the gorilla with one of her kittens)
Elephants Painting