A cordial good-bye to you. This intrusive imperative became extremely common after 1950 among U.S. truckers who used it on their citizens-band radios. In Britain it often is put as have a fine day or have a good day. The latter, which may have its origin in the Middle English have good day (ca. 1200) and was frequently used by Chaucer, apparently died out for some centuries and then was revived. It is often heard in America and occasionally is altered to have a good one. Since the late 1960s these phrases have become ubiquitous. They often are used ironically, either knowingly or unconsciously. Following a precipitous drop in the New York Stock Market in October 1987, the telephone clerks employed by Pacific Brokerage continued to report to the company’s clients, as they always had, “This is Pacific Brokerage Calling. You just sold 30,000 shares of Widget Manufacturing at $1. Have a nice day.” Conceivably this message might have driven the investor who bought Widget at 32 straight out of the nearest window. Or take the insurance agent who said, “I’m sorry to hear about your husband’s death. Have a nice day.” By about 2000, however, have a nice/good day had largely become a synonym of “good-bye,” and was taken no more literally than the “God be with you” that was the original source of that word. A related term increasingly heard in restaurants is Have a nice meal, which similarly induces teeth-gnashing irritation when voiced by a particularly incompetent waiter.