Agreed, also i like to stack my bag very methodically with heavier and more sturdy items at the bottom, cold things together, interlock and tetris everything so the bag has its own integrity and doesnt collapse and spill items out into the car after a corner.
Yes i know the checkout person also stacks in a similar fashion but they are paid the slap it through and into a bag as fast as possible to serve the next customer and i dont mind sacrificing an extra 15seconds of my day over the bag stacking operation to do it right.