This, while a GREAT scene in the movie sums up the issues with Joker on the ground level. He just does... random shit... cause he wants to do random shit.
When a villain's whole purpose is just chaos and mayhem it gets boring to me.
It's why even though I hate how they made Bane basically into a puppy dog following orders in the 3rd Nolan movie I prefer Bane to Joker.
Both Bane and Joker have the charisma to gain followers. But all of Joker's followers are bat fucking shit insane and just prone to mayhem. Bane's followers, all intelligent and they all can follow orders to a T and because of that are more dangerous in my eyes.