Quoted in Evan Esar, The Dictionary of Humorous Quotations (1949). Colonel Tom Parker, Elvis Presley's manager, is said to have remarked, "You don't have to be nice to people you meet on the way up if you're not coming back down again."
Paul Watzlawick, John H. Weakland, Richard Fisch (2011). “Change: Principles of Problem Formation and Problem Resolution”, p.11, W. W. Norton & Company