From PJ O’Rourke, “Modern Manners: An Etiquette Book for Rude People”

Heroin and the other “downs,” natural and synthetic, are not polite. These drugs effectively eliminate the painful aspect of existence, which, nowadays, is almost all of it. Pain, such as a pain in the ass, is the thing that commonly alerts us to the presence of other people. Interaction with others is what manners are all about. Don’t take “downs.” Try to be “down on life” instead.