Why does my cat pretend to hate other cats ?

Question

lol, this may sound stupid, but when i look out the window, i see my cat lying down by this other cat and like sleeping, they are always doing that, and when i come home and they are in the grass lying down together, my cat see's me and she goes crazy and hiss' at the other cat and everything, its like shes pretending to hate the cat when i come around, i dont know if that's accurate or not, what do you think?

Answer 1

It's as though she's saying "I'm your cat and that other cat is not so don't get confused just because I'm lying next to it." And then as soon as you go the cat will say to the other cat "back off, she's mine" and go back to sleep.

Answer 2

That is her way of telling the other cat that you belong to her. She doesn't hate the other cat just wants it to stay away from her mommy. So don't worry she is not nuts, just nuts about you.  

Answer 3

You have a psychotic cat, but don't worry, they all are.  That's what makes them special.