The hiss of the beer tap is the first sign of trouble. I hadn't ordered any beer; arriving for lunch, I'd said "two people", as an oversimplification of "Good afternoon. A table for two, please."
As usual, I'm carrying a phrasebook, but everyone here speaks such good English that using it is a waste of time. I settle for stripping down my normally highly obfuscated speech as a compromise. Somehow, though, "people" has gotten twisted into "pivo". It's the equivalent of walking into a classy restaurant, stepping straight up to the waiter, and saying "Two beers!", or possibly "Grog want beer!"
Now I have a problem. If I'm surprised by the beer, then I have to explain why, and there'll be complications, and I won't get any beer. If I'm not, then I'm ratifying my earlier rudeness. I have ten seconds to decide. On balance, I decide to Go With The Flow - the best travel rule we've ever come up with. So when the beer arrives, I just stare and stammer. For the rest of the meal I'm ultra-polite. No doubt a waitress somewhere in Prague has some stories to tell about Aussies - normally lovely, barbaric when they're sober.