The only place worse than D.C., by a very narrow margin, is Hawaii, where folks give up an average of 14.8 percent for tips.

Ah, the holiday season — the time of year when you make the people that keep your day-to-day life on the tracks aware that you appreciate their effort. Postal workers, sanitation employees, your paperboy or girl, a doorperson if you have one — it’s always a smart move to make sure that you keep those people happy. Some neighborhoods and apartment buildings in Washington even take up an envelope or jar and present their local servers with a collective gift, which kind of makes us feel all gooey inside. But if you were thinking about tipping with cash, you might want to think again.