Medical doctors can have the letters “MD” on their cars’ license plates, which in some places can help them bend the rules regarding parking and speeding in emergencies. But if you’re at all like me—and for the sake of your loved ones, let’s hope you’re not—you have one of three highly prejudicial and unfair reactions when you see a car with MD license plates. For a fancy vehicle: Ooh, look at Mr. Big Shot driving a six-figure car. For a piece of junk: What kind of crummy doctor drives that piece of junk? For any other auto: “Emergency” my butt; you’re probably my dermatologist. (By the way, none of these opinions are in effect if the doctor is rushing to care for me.)