Friends you know to be dead are having lunch together. Although their table is crowded they seem happy to allow you to sit with them. "You understand," you tell them with a certain earnestness, "you're all welcome to visit with me any time you like." In response there's an undercurrent of bored amusement. "You realize that's not how it works," says one, a little impatiently you think. You nod. "I'm simply expressing good will," you say, and everyone smiles. Your sincerity is clear to all.