Good manners in general are Quite Useful by providing heuristics which enable civilized people to interact in a genteel way. Over the past few months, I have identified an additional benefit - as a repellant to Highly Annoying People. From time to time, I receive an invitation from some long disconnected person wishing to get back in touch and to "do lunch". I loathe gratuitous lunches with people I barely know; but some people are incredibly persistent, causing me to succumb to an appointment just to stop the annoying messages. After a few of these over the past couple of years, I discovered The Repellant: paying for lunch. If one pays for lunch with the added "next time is your turn", one never hears from the annoying person again. I consider this a Very Wise Investment.