Morning thought:
When you train someone else in a difficult task, you cannot do it effectively by starting them with the most difficult part of the task and expecting them to get it right. They just won't have any basis for even understanding what they're supposed to do.
On the other hand, you can't go to the other extreme and simply give them the simplest parts of the task, over and over, with no progression. They'll get bored and will never learn anything new.
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@DavidSalo In the dojo I have to counsel my more advanced students to perceive and challenge the juniors, not to overwhelm. They also need this perception when dealing with more advanced people, but the senior should set the level based on where the partner is. Each member of the pair might learn something different but they both learn something. The only advanced ones who are all like "I'm a shame dis beginner" are people coming in from other styles - so I have to make your point to them.