I used to train boxers. Day One: put them in a proper high guard; hit them in the face/gloves. I can tell pretty what I need to know about how to train you by the way you react to that punch. Best reaction, IMO, is if they step toward you while keeping the guard. That's pretty much the perfect blend of thought under pressure, aggression, and instinct. That said, there are sometime people who will be better off with just running/retreating. No judgement...that's just how it is.