I don't think those moments are limited to seniors! I think it is more matter of focus. We get into rhythm and our minds wander. This can get very dangerous when working with our tools. I was teaching a basic sewing class and when I demonstrated the rotary cutter, I got distracted and cut off the side of my index finger- to the bone, slicing thru the artery. Spent the next 8 months sewing with a finger cage - a super challenge. Lesson learned - I take a break at least every hour to get a drink of water, pet the animals or just gaze out the window. A couple minutes really improves focus.