Eric Berne, M.D. (1910-1970)

Belching at meals or asking after another man's wife are each encouraged or forbidden by local ancestral tradition, and indeed there is a high degree of inverse correlation between these particular transactions. Usually in localities where where people belch at meals, it is unwise to ask after the womenfolk; and in localities where people are asking after the womenfolk, it is unwise to belch at meals.

        — "Games People Play"