I've noticed that when I take people out with me, they tend to spend most of the time watching where they put their feet and hands and don't look up often enough. I think this may be a reason for a lot of accidents and lost hikers. Surveying your surroundings should be as natural as looking in your rearview mirror when you drive. Everything can change in just a few steps. One of the things I do before we go out is I tell them that I will test them as far as their observations go. When I notice them not paying attention, I will take 2 steps off the trail to see how long it takes them to notice they are alone. I never let them out of my sight so there is no danger in getting lost. Some have taken as many as 20 steps or so to notice they are alone. After that they look up more often. So many things can change in 20 steps. While it's important to watch where you put your feet and hands, it's also important to look around for dangers and landmarks too.