Few plays are more humiliating than getting dunked on. You can shrug it off when someone makes a tightly-contested shot in your face. Sometimes the hoop does appear larger in real life than in the mirror. If they happen to cross you over in a rather nasty way, at least you still have your bearings.
But to get dunked on? To have your entire defensive mystique as an athlete called into question? To be memorialized in a niche poster? That’s forever, and you don’t forget the overstep.