There's different kinds of lessons. There's a kind of instruction that's given to a beginner, then instruction for more advanced players, and then you've got instructions involving gaming situations and how to play certain games.
I watched Mizerak give a one pocket lesson to a guy. It was great. It was not a bunch of if you're here do this or if you're there do that, it was a philosophy of the game.
How to evaluate balls, your side of the table, his side of the table and so on. He wasn't teaching the what to do but the how and why you were doing it so you could use the same evaluation on any shot. I guess that's the way you would expect a real teacher to teach, the student has to know why he's doing this.
I used to play with the Diliberto a lot not lessons just practice but they always seem to turn into lessons. There would always be points where I would do something and he quiz me on why I did it that way and then we would talk about it.
This was not to be critical just to maybe give me another perspective on the situation. He also would show me things that worked for a player of my skill level. In other words not necessarily what he would do, but what I should do.