Don't play her game. Leave her out there - who cares what you look like to everyone else? She is banking on you to care about what you look like to everyone ;) If you take that part out of the equation all you have is a grown woman acting like a 2 year old.
Would you hand DS the lollies because he had a narna on the floor of the supermarket?
I find in these situations it's all about keeping the focus on THEM. Huffing, sulking and making cryptic remarks are all to throw you off balance and keep you on your toes. I keep to the subject and wave away the smoke and mirrors "you don't need an education to have an opinion mum - I still like the green one" eg.

