I underestimate turns-always walking into walls next to hallways or whacking my arm on them at least... I always slam into doors (usually after forgetting that I've closed them), but my biggest problem is when I bend over to look at something in a store, off of a clothing rack usually, and I whack my head right on the metal bars that hold the clothes if I'm looking at something the next one down (usually when looking for clothes for my daughter). It's embarrassing, and I do it every single time! I also do it repeatedly sometimes, I'll get ready to walk off then decide to look at it one more time and whack! again, as if I didn't learn the first time.