1 Today there was a tai chi class, and people were more late than usual. To make the instructor, who's students other than myself never show up on time, although I do, I stated the weather might be factor.
When only other student that day showed up, the instructor suggested that I made that remark, making both of us feel uncomfortable. I didn't say anything to create any more tension.
I did make some other jokes, so we might be distracted from the inappropriate remark.
2 Another embarrassing situation was that I had a manicure, and some shiny substance made my nails stand out at a business meeting. In the future I asked for nothing on my nails.
3 When I received my cellphone at work, I talked publicly in mixed company, until I understood it was inappropriate. Since then, I always had my phone on silent(vibrate),etc.