I have two - First when I go to my usual quilt shops, I am always treated very nicely, but, when my 24 year old daughter (who looks about 16) goes in without me she is snubbed. There was one shop in particular that was the worst offender. So during a Quilters Run (while the shop was very full), I told them why I never shop there anymore. Three other ladies came up and told me they were glad I had spoken up.
Second story - I bought $53.20 worth of merchandise. I gave the lady $60.20. She started to give me change of $6.80. When I told her I had given her 20 cents, she stood there and practically called me a liar! I did go in again the next week for something and she apologized, but still left a bad taste for that store.