A selectman in my town was Kerry's paperboy back in the 70s when Kerry lived in Lowell, MA. Out of his 40 customers only 2 never gave him a tip. Guess who one of them was?
Hardcore socialists, both advocates and beneficiaries, never tip. One of them actually laughed in my face when I told where he could write in a tip on a credit card slip. Another actually took his time to count out the exact amount of the transaction, and not one penny more, while I was standing outside the door in cold pouring rain.