you're entirely correct, but what people are also missing is: if the weather's nice, getting outside and pushing carts is a welcome break to the fluorescent lights and other drudgery of the store...
anyone who's ever actually worked a retail job will tell you that going outside every once in a while is pretty nice.
picking up trash in the rain sucks, but pushing a cart is leisurely compared to whatever else they'll have you do.
you click the enter key...