To go further on the subject –
Certain types of lights are used to make certain products look more attractive. White/slightly blue light in the grocery section (makes green more green, red more red etc.), red/pinkish light in the butcher area, to make the meat look more red than it is.
Some shops even play sounds, to make people buy stuff. IKEA pumps the smell of their cinnamon buns (which you can buy “freshly baked” just after the registers) through the whole shop, to make you crave it when you reach the restaurant, or at least when you leave and pass them (“ah, that’s what I smelled). A supermarket I worked in, did the same as IKEA, but with the air coming from the bakery.
And there are dozen of tricks to make people buy or crave more stuff. Reason why vegetables are first? So you feel you are allowed to buy something unhealthy when you pass the candy etc, because you’re also buying vegetables. If it was the other way around, you’d probably say “nah, too unhealthy” when you pass the candy and afterwards just buy the same vegetables.
It’s a multitude of techniques used that your usual shopper won’t even notice. It’s an interesting field of psychology and a lot of shops are also used as testing areas for some theories of human behaviour.