Do people really enjoy being sung “Happy Birthday” by the staffers in restaurants ? Maybe there are two types of people: the kind who really love birthday attention and want to celebrate with everyone around, and the kind who shy away from big displays of attention, like getting the waitstaff to sing for you at restaurants. We've all seen it play out. A family will come in to dine, and one person will find the waiter in private and tell them to surprise the birthday person with cake. That often…