on my first visit to the US back in 1982 I was rather younger than I am now and somewhat less aware of cultural differences. Thus it was that I found myself in a restaurant ordering dinner. I wanted a steak but was first interrogated within inches of my life about the salad! Did I want a green salad, a ceasar or bean? I went for green. What dressing did I want? A dizzying array of dressings (most of them disgusting ).
Now you have to understand two things here. The first is that this was the first time I'd ever been outside of Australia. The second is that in the Australia of that time salad wasn't considered as a course unto itself. It was always a side dish. And so the salad arrived, alone. 45 minutes passed, during which time I didn't touch the salad. Eventually the waitress came over and asked if there was anything wrong with the salad. 'Yes' said I. 'It's a bit lonely - where's the steak?'. Confusion reigned. To this day I'm not sure she understood why I hadn't touched the salad.
Ever since then I've always watched how other diners do things. No, I won't take the actions of one diner as gospel; but if I see 7 diners doing roughly the same things in an unfamiliar milieu I have reasonable confidence that doing the same things won't be out of tune with local custom.
On the other hand, some things are hard to overcome. In Dallas this week one of my fellow workers hailed from Singapore. He makes the kind of noises when eating that we Australians and Scotsmen and Americans and Englishmen don't make. I really had to remind myself that silent dining is a Western thing. And I'm not sure I could ever bring myself to make those kinds of noises even knowing that such noises are considered polite in other cultures.