Maybe this thread title should be WHY do you work on what you work on first day back for the season? So far, at the heart of most of the serious contributions here to fore, is the ability to properly balance. Most all the subjects in
@geepers first video talk about balancing through the arch. More importantly, balancing through the arch in relation to one's sagittal (Fore and Aft) plane.
For most, there are few activities in the off season that require us to (while on the move) reliably and consistently align our mass though the center of the arch using the flex complex (ankles, knees hips) as regulators in such a combination that we allow for pressure management and dynamic balancing against the continual changes in slope and lateral angulation, not to mention lack of friction. When on edge, feeling the arch compress between the back of the ball of the foot and the front part of the heel is a sure sign that you are in position to work and ride the ski.
So it is no wonder that when you strap on the boards after months of using heel to/and toe based balancing (be it static or dynamic) that your body and brain need a refresher course in how you successfully balance on skis.