Half of my parents' neighbourhood's cats love getting into fights. If a strange dog entered their territory (and attacked their property), they'd make him pay just of the hell of it.
They're surprisingly nice to other animals they do know, though. For years our rabbit hutch was the favourite lounge area of half a dozen cats. Now that I think about it, when some of my parents' friend brought their dog with them and let it near the hutch, our cat bravely defended that fortress with lots of swiping and hissing.