For all you table teachers out, I am sure that you have noticed this phenomenon. Week 1: "Don't lead dummy's seven card suit even if you have to revoke."  Week 2: "Second hand low."  Week 3: "Don't make a plan that involves purposefully taking ruffs in the hand with long trumps." Week 4: Leads Dummy's seven card suit. 3 other choices available. Week 5: Declarer leads low, goes up with Ace. Week 6: Ruffs dummy's long suit in hand, loses control, goes down in a cold contract.

My point being that plays and retention seem to be more or less random anyway. So why do we:

Focus on the elimination of errors rather than the reinforcement (and hopefully repetition) of all the myriad little things that are done right in the course of a session.  I find that even when I resolve to "teach positive" I am much more attuned to errors that need correcting than I am to accurate choices that could be reinforced.

Have you tried this? Have you overcome your impulse to criticize and correct?  Can you help me do better?