Adapted from the joke I found on this other blog.
Once, there was a very kind old barber in New York.
One day, a florist goes to him for a haircut. After the cut, he pays the barber but the barber replies “I’m sorry. I cannot accept money from you. I am doing community service.” The florist is happy and leaves the shop. The next morning when the barber goes to open his shop, there is a thank you card and a dozen of roses waiting at his door.
A policeman goes for a haircut and he also pays the barber after the cut. But again, the barber replies: “I’m sorry. I cannot accept money from you. I am doing community service.” The cop is happy and leaves the shop. The next morning, when the barber opens his shop, there was a thank you card and a dozen of donuts waiting at his door.
A university student goes for a haircut and he also pays the barber. The barber says: “I’m sorry. I cannot accept money from you. I am doing community service.” The university student is happy and leaves. The next morning, when the barber goes to open his shop, guess what he finds there:
A dozen university students waiting for a free haircut!