DEAR MISS MANNERS: I contend that buying a round of drinks when out with friends is like giving a gift, in that one should do so without anticipation of the gesture being reciprocated. It is a way of saying, “I am grateful for your company, and here is my effort to enliven our night out.” “Bosh,” says my friend: Buying a round of drinks is an established custom, in that over the course of the evening, each person is expected to take his or her turn. Please let me know whether to be smug or admonished. GENTLE READER: Buying a round of drinks should not come with an expectation, but it is always…