You pick up your baby from day care straight from work. You have a handbag, and a laptop bag. You have to balance these while pushing your stroller along - with the baby's bag hanging over one of the handles. You walk with a slight bend in your posture so that your laptop bag doesn't swing around your side, you struggle to keep everything in check..

Baby wants a snack..... Then a drink.... Stop, start.... Stop, start.... More balancing!!

You make it home! But with a back ache for your troubles. 

Or you could just hook everything on your stroller.....