Many years ago, I was sitting in a restaurant in Osaka eating some delicious gyoza. I'd got about halfway through my meal when the chef, who spoke no English, came out from the kitchen to my table and was gesturing at my chopsticks. Apparently, I was using them wrong and he couldn't stand watching me do this any longer, so took it upon himself to come out and show me the "correct" way!
While slightly embarrassing at the time, I've been using my chopsticks "correctly" ever since! Something...