Trolley Psychology

Supermarkets spend millions of pounds researching consumer behaviour in order to develop tactics to compel us all to buy more in their stores.
The products that make the largest profit margin will usually be found at eye level - you won't usually find a bargain in the best shelf spots so it pays to look further up and down.
The ends of the row are often the most profitable area for product manufacturers and they often pay a premium to have their product placed there. These displays also act as a welcome mat to lure shoppers further down the aisle.
Last-minute temptations such as chocolates, lollies, magazines and cold drinks are all located here to entice bored, tired shoppers (and their children) while they wait to be served.
Essentials such as bread and milk are placed at the back of the store, often at either end. This is to entice shoppers to buy other items on the way.
Products that are a good match - such as coffee and biscuits - are often placed nearby to prompt you to buy both items.
The most common path to travel is around the outside perimeter - dipping in and out of the aisles as needed.
The fruit and vegetable section is located right near the entrance - it's there to help present a fresh and healthy image. It's also designed to look like a marketplace, which encourages shoppers to stay in-store longer and to spend more.
Right-hand entrances encourage shoppers to travel in a counter clockwise direction - research has shown that shoppers that travel in this direction spend more.
However I am guessing that further research is needed into why shoppers at my local "Orrisons" routinely use trolleys to block off the roads leading to the store.