Here's an etiquette question: last weekend I went to a jam and sat beside an older man who I hadn't met before. As another person started a song - and before I had played a note - he turned to me and said, "Key of G, dear. One sharp!"

As I don't know how to talk to people, I didn't say anything, but now I wish I had said, "What's a sharp?" What, if anything, would you have said?

You may think I'm overreacting to what was intended to be helpful, but I found it quite irritating that he assumed that I needed this (very elementary) help because I'm a woman, or significantly below average age in this jam, or both.

Marion