I think the question is the same as someone asking "Why is riding a bike so hard?" and the answer is simply "Because you didn't learn to do it well enough, yet.

I think the question is the same as someone asking "Why is riding a bike so hard?" and the answer is simply "Because you didn't learn to do it well enough, yet." FOr someone doing the same guessing for 20 years it is not hard at all. In fact he probably doesn't even have to think about it. The perfect result will just pop up in his head (or a result so close that the error margin doesn't matter for that exercise). Is that thought so unusual? I don't really see, why it needs to be discussed, what makes a beginner guess wrong. The solution will be always the same: exercise or let someone do the task, who has the experience. Could someone explain the point of this discussion to me?