Is the clown Batman's greatest enemy?

Clowns should be Batman's "best" enemy. The purpose of things like double-faced, scarecrow and Bain is to defeat Batman (Bain once succeeded), while the purpose of clowns is to disintegrate Batman mentally. He has been attacking Batman's friends: turning Harvey into a double face, killing Robin, maiming Gordon's daughter, trying to drive Gordon crazy and making Batman more and more lonely. The clown and Batman should be said to be the best pair of old enemies. They are actually a kind of people (please refer to the comic book "Killing Jokes"). Both of them are crazy because of a bad day, but one is crazy to do good and the other is crazy to do bad. The most telling thing about their relationship is that the clown told a joke at the end of the comic book "Killing Joke", and then under the lights of the police car, the two men laughed wildly.