why so serious

"[speaking to Harvey] Do I really look like a man with a plan, Harvey? I don't have a plan. The mob has plans, the cops have plans. You know what I am, Harvey? I'm a dog chasing cars. I wouldn't know what to do if I caught one. I just *do* things. I'm a wrench in the gears. I *hate* plans. Yours, theirs, everyone's. Maroni has plans. Gordon has plans. Schemers trying to control their worlds. I am not a schemer. I show schemers how pathetic their attempts to control things really are. So when I say that what happened to you and your girlfriend wasn't personal, you know I'M telling the truth. [hands Dent a gun]"
"It's a schemer who put you where you are. You were a schemer. You had plans. Look where it got you. I just did what I do best-I took your plan and turned it on itself. Look what I have done to this city with a few drums of gas and a couple bullets. Nobody panics when the expected people get killed. Nobody panics when things go according to plan, even if the plans are horrifying. If I tell the press that tomorrow a gangbanger will get shot, or a truckload of soldiers will get blown up, nobody panics. But when I say one little old mayor will die, everyone loses their minds! Introduce a little anarchy, you upset the established order, and everything becomes chaos. I am an agent of chaos. And you know the thing about chaos, Harvey? It's fair. "

The Joker, Clown Prince of Gotham, The Dark Knight