This works for you because you live in a society where a significant majority of people are trying to be nice towards other people. Because you choose to ignore the social contract of "let's all try to be nice" you can circumvent the drawbacks of that agreement. If everyone actively pursued your approach, however, we'd be in a mess. Also if you encounter another asshole, it becomes survival of the fittest. And again because you live in a "nice" society chances are the other asshole doesn't have a lot of experience at being an asshole. But sooner or later you come across a colder and smarter son of a bitch than you.