By Ariane Sohrabi-Shiraz If you think you know all there is to know about supermarket trolleys, think again. Supermarket trolleys are self explanatory, right? They have four wheels, a slot to input a pound coin, and usually some sort of seat for a baby or toddler to sit in. Well, it turns out you’re wrong. Have you ever noticed that hook that is attached directly under the trolley handlebar? Well, it turns out it’s not just for decoration. It has a very clever use – and people’s minds are blown. The revelation was shared by a Woolworths employee in Australia, who uploaded a video to Woolworths…