Have you never noticed that the interior arrangement of the shops is similar to each other? Where the stores arrange the items in an intentional order and not randomly, so they place the important products at the end of the store.
For example, suppose a mother and her daughter went to buy some vegetables from the store and when they entered the store and found a lot of sweets and chocolate in front of the store door, of course the little girl would want to get some and if the mother refused, the little girl would cry until she got it in the end (especially a Kinder egg)
Then the mother will pass the cleaning powders, she will find some discounts on her, and even if she does not need them, she will take at least one because there is a reduction.
Then comes the role of dairy products and then meat until finally they reach the main purpose for which they came, which is vegetables, so instead of buying vegetables only, she bought sweets, cleaning powder and maybe some cheese and vegetables!
Even if you are strong-willed and only buy what is required, you will find many products around the cashier that may entice you and buy some.
An additional tactic: Don't you wonder why if the price, say $ 4, is written as $ 3.99? What difference made this one cent!
Because you will read the numbers from left to right and you will take care of the main number and will not catch your eye on the few coins because your mind loves saving energy, so you think that it is only three dollars until you reach the cashier.