Answer the troll's riddle and see if you can make it laugh.
The troll would have more personality if it had more things to say. What should it say if you try to "go" without permission? Or what should it say if you try to "hit" the troll?
The troll program is called a "chatbot". Chatbots can have all sorts of conversations, not just riddles, and some chatbots are good enough that they can fool you into thinking they are really a person. Can you make a chatbot that chats like a person?