Stores use scientific tricks to get us to buy more things. At many stores like WalMart and Kroger, when you walk in, the fresh produce and maybe bakery are immediately to your right while the cash registers are to your left. They are positioned that way to steer you toward the right. 

After many studies, they have found that humans are just as easy to predict as migrating animals. Stores that place their doors to the right instead of the center or the left do much better. The stores are laid out to lead you on a set path. They place the produce to the front, because the first thing seen is bright, fresh, colorful food. 

The customer then translates that into thinking the whole store is bright, fresh, and colorful. If Doritos were placed in the front, on a midnight snack run, you’d grab them and go straight to the registers. 

By placing snacks strategically in the back, though, the customer gets distracted and sees other things they could buy. The goal is to keep you in the store as long as possible. They put the useful things, or things you need the most often like cheese, milk, and eggs, towards the back. 

By the time you get to them, you’ve passed lots of other things, realized you need them, and your cart is full. 

(Source)