There are a large number of small things that are easy to learn, yet which at the same time are utterly impossible to figure out. If someone shows them to you, them look like the easiest thing in the world, but if you have to speedlearn them on your own, difficulties ensue.
A dramatic example of this is a young man finding himself in the situation of having to unclasp a bra. It is a very small thing indeed, and the logistics involved can be performed without much thought, and yet. Difficulties ensue. Possibly also a non-zero amount of fumbling.
Similar (possibly, but not always, less dramatic) instances of small logistics occur just about everywhere, most of them having become so routine it takes an act of effort to notice them. Computer interfaces, what to say when ordering fast food, the art of performing an academic citation - these are all instances of small logistics where the knowing of how to get it done has merged into the back of one's mind. Once upon a time you had to learn these things, before they became obvious.
It pays off to pay attention to these things. Not only do you become aware of what you are (quite literally) doing, but you also gain the opportunity to think about other ways of doing these very things. And, if you notice someone not quite knowing how to move things along, the insight into just what they need to learn for future reference.
It's the little things, as the saying goes.