Come Here Often?

So I work at The Crystal Bar and Bridger Brewing Co. I know gaggles of regulars-their names, preferences, place of work, significant others, and what they ate for dinner last night. One thing can be said for nearly all regulars: they're consistent with what they eat and drink. Consumers become overwhelmed with too many choices and default to what they already know, or in this case, what the bartender already knows about them. In a bar full of thousands of possibilities, why do we sell more PBR and well whiskey than anything else, when both options are relatively mediocre? In a restaurant with hundreds of pizza combinations, why do we sell more pepperoni and meat-lovers' pizza than any other style? When in doubt, we stick with what we know.