DEAR ERIC: I am a mahjongg instructor and enthusiast, and I run a mahjongg social at a public park. We have a group of anywhere from 20 to 50 players meet up and use tables reserved for our group.

I told her it was too complex to learn that way she began to berate me and ask me personal questions about whether I have ever been excluded.

When I said she was welcome to watch, she berated me and asked personal questions about my experience with exclusion. She ...