I made some disparaging remark about mashed potatoes being good only for adding to bread dough and Sarah said "Haven't you ever made potato soup with mashed?"
No, actually, I hadn't. But I tried it and it was good. Then, last Sunday morning when I quickly made up a pot of hamburger-soup I was a little short on time for peeling potatoes, which the recipe doesn't call for but I like to add. I had almost 2 cups of leftover mashed and I just popped them in and stirred until they disappeared. Marvelous use for something that otherwise sits around until its old enough to dispose of.
Thank you Sarah! Best tip ever.