On quiae a number of flights I have experienced other PAX applauding landings, in what have been fairly benign conditions.
It's always struck me as slightly odd, since I don't get a round of applause when I "do my job" - why should flightdeck crew be congratulated for simply "doing what they are paid for".
Incidentally, I don't think any one nation or culture is prone to this behavior - I'd seen (heard) Brits, Germans, Americans etc all doing it from time to time.