Did you ever plan a dinner party and consider inviting a new guest? Or a weekend trip - shopping excursion or hunting trip, with space for one more person? How did you decide whom to choose? And how did it turn out - amiably, with a prospect of a new lifelong acquaintanceship? Contentious because of differing personalities and social styles? Or just nothing much, and you’re left with regrets because the newcomer sort of faded into the woodwork, obviously not having a good time?