How many times have you walked into a grocery store for eggs, only to come out with $250 worth of stuff you don't really need? Since the earliest grocery stores opened, people have fallen prey to simple tactics designed to fill their carts and empty their wallets. How grocery stores trick you largely depends on time; the more minutes you spend near the shelves, the more money you're likely to spend. Retailers will do anything to suck you in, from placing the most commonly purchased items all the way at the back of the store to playing slow music that makes you linger.
But don't worry - grocery stores aren't actually out to get you. Overall, they have a lower profit margin than other retail outlets like clothing stores and electronic retailers. But they've got to stay in business somehow. The average person heads to the supermarket one and a half times a week, completely blind to grocery store secrets that suck them in and have them leaving with 10 bags of potato chips and bottles of soda - not to mention that cake.
Read up on the ways grocery chains get you to spend money, and consider trying a few grocery shopping hacks the next time you head out to stock up the fridge.