Start with these questions:
How's work going?
Any plans for the summer?
How was your (insert holiday)?
If the customer is polite, they will ask you the same questions in return. And for some reason, people getting their hair cut think barbers live boring lives. Obviously, and as the great tapered-military-cut craze of 1998 showed, this couldn't be further from the truth. But keep up that image.
Give vague answers where you shrug and say things like "it is what it is" and "I'm thinking of opening a new shop downtown." The latter will make them feel good because they'll think they're giving you so much business that you need to open up a supplementary location. People like to feel good about themselves. And that's priority number one: providing a positive experience.
Strike that. The balls thing is number one. Always.