Dialogue (slightly edited):
Batman: You think you're my greatest enemy?
Joker: Yes! You're obsessed with me!
Batman: *pfft* No, I'm not.
Joker: Yes, you are.
Batman: No, I'm not.
Joker: Yes, you are! Who else drives you to one-up them the way that I do?
Joker: No, he doesn't.
Joker: Superman's not a bad guy!
Batman: Then I'd say that I don't currently have "a bad guy." I am fighting a few different people.
Batman: I like to fight around.
Joker: Okay, look, I'm fine with you fighting other people if you wanna do that, but what we have? This is special. So when people ask you who's your number-one bad guy, you say...
Joker: Are you seriously saying that there's nothing, nothing special about our relationship?
Batman: Whoa. Let me tell you something, J-bird. There is no "us." Batman and Joker are not a thing. I don't need you. You mean nothing to me.
* * *
Batman: I hate you.
Joker: *gasps* I hate you, too.
Batman: I hate you more.
Joker: I hate you the most.
Batman: I hate you forever.