I will NEVER understand why mothers think they can say anything they like to their grown children. I have friends who do that to their children. If I did the same to my daughter or son they would never speak to me again. PLUS when I'm jokeing with my daughter she reminds me very sweetly that SHE will get to pick my nursing home.
My mother always felt free to tell me a better way to do things. It made me mad but for the most part I just ignored her.