I was replying to a poll here on A to Z about the number of years we have taught. As I replied, I thought about how I finally feel like I know what I'm doing and how glad I am that no one knows how many mistakes I've made along the way. One of my most common mistakes in my earlier years was in the way I taught. I thought that as long as they were busy, they were learning. Now I know and understand words like "busy work". Ooops!! Hey, you live, you learn! I never give busy work now--we don't have the time with all the material we need to cover! What are some of your more memorable "ooopsies" in teaching over the years?