John I hope you have also got the lift fairy explanation for stalling.
Which is when the wing reachs the critical angle of attack the lift fairys are unable to hold onto the wing any more and slide off the upper surface of the wing to hang onto the trailing edge where they bounce around giving a rumbling noise. When you reduce the AoA they can climb up again.
Vortex generators give them something to hang onto.
Its quite scary how much you can explain with "lift fairies" theory.