Hes throws the wine out of the glass on purpose. It looks like a joke but i beleieve this joker doesnt drink BECAUSE his father was a drinker and a fiend. And after he does this he tells a guest you remind me of my father.
Joker hates people in authority because he hates powerful men who believe they are above the law. He helped weaken gothams mob because they are above the law. He shot gordon because gordon was the head of gotham PD. He destroyed harvey because harvey believed he was morally superior. And he took down batman because he was a vigilante. This joker is very anti authority and i believe hes like this because of how his father abused him.
People think both stories have to be lies but they dont. This joker could very well be into self mutalation. If you ever seen a real glagslow smile they arent that thick. I believe that his father did carve his face, and carving his face since then became a massive form of self mutalation. He eventully started wearing clown make up to try and hide his scars. This explaning the joker persona.VidMateMobdro