It pulls left. Always left, or nearly always, though a produce clerk of twenty years' standing insists that easterly carts pull right in his store, and that this is apparently a whole taxonomy unto itself, cart drift correlating with something in the caster's manufacture that nobody bothers to fix twice. Study the abandoned carts along a single lot, unscientific but sincere, and the numbers hold: eleven surveyed this spring, seven pulling to one side, two rolling true, and two so committed to spinning in place that the axle seems to have given up on forward motion as a concept entirely. The wobble comes from a single wheel, usually the front right, worn oblong rather than round, so the cart does not roll so much as lurch in a four-beat rhythm you can feel through the handle before you can hear it. Pushed empty, it announces itself a block away. Loaded with groceries, the sound changes pitch, drops an octave, becomes almost apologetic.
No one is ever seen complaining to a manager about this. People simply abandon the cart mid-aisle for a better one, the way you would leave a bad table at a restaurant, quietly and without confrontation. Reported to no one, fixed by no one, it remains the single most democratic object in the parking lot: everyone gets exactly one bad cart eventually, and everyone recognizes it by the same four-beat rhythm before they have even reached the handle.