When I pluck, my bow arm moves left and I hit left. When I collapse, my bow arm moves right and I hit right (usually quite far right). My plucks come from using too much muscle other than back and trying to "hold," rather than pulling (my anchor stays in place, but the "pull" never stops, if that makes sense) through the shot. When I "hold," my hand will fly out sideways rather than back and into my shoulder, and the bow will jump the opposite way, rather than going straight to the target. This is my most common form mistake, and I am prone to shoot left.