And of course there's also the chance that some unseen Vietnamese or Cambodian was downrange when I was shooting out into the darkness. That doesn't count as meeting people either.

I was in an armored unit: the 11th Armored Cavalry, the Blackhorse Regiment. Infantrymen probably saw more of the real local people, but not a lot more. The tens of thousands of U.S. personnel working out of air-conditioned buildings in Saigon, Long Binh, and other centers saw merely a large-scale version of the Coke girls, hooch maids, and boom-boom girls whom combat units met. The relative handful of advisors and Special Forces were the only American citizens actually living among the Vietnamese as opposed to being geographically within Viet Nam.

I very much doubt that things were significantly different for soldiers fighting foreign wars at any other period of history. Sensible civilians need strong economic motives to get close to groups of heavily armed foreigners, and the needs of troops in a war zone tend to be more basic than a desire to imbibe foreign culture.

Soldiers aren't any more apt to like all their fellows than members of any other interest group are. In school you were friends with some of your classmates, had no particular feelings about most of the rest, and strongly disliked one or two. The same is true of units, even quite small units, in a war zone. The stress of possible external attack makes it harder, not easier, to get along with the people with whom you're isolated.

And isolated is the key word. We changed base frequently in the field. One day we shifted an unusually long distance, over fifty miles. The tank I was riding on was part of a group that got separated from the remainder of the squadron. We had three tanks, four armored personnel carriers modified into fighting vehicles (ACAVs), an APC with added headroom and radios (a command track), and a light recovery vehicle that we called a cherrypicker though it had just a crane, not a bucket. We ran out of daylight.