Full-size candy bars are the holy grail of Halloween. For many trick-or-treaters, they are seen as the ultimate bounty—a proper, grown-up Snickers or Milky Way with which to mock less-fortunate peers before engorgement. For those giving out the candy, they offer a not-so-subtle way to outdo the neighbors—Halloween as potlatch. The house with the full-size bars is the best house on the block.

Though tempting, the practice is wrong-headed. Giving out full-size candy bars misses the point of Halloween. Here’s why.

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It’s not clear when the fun-size category first appeared in the candy aisle. Hershey’s Miniatures played the matter straight for decades. They were small versions of traditional bars. Then bite-size candy appeared in reception-desk bowls and Halloween tubs. As a descriptor, bite-size is both accurate and soulless. Though mostly a marketing term, fun-size is the right way to think about Halloween candy from a gastronomic perspective.

To understand why, it’s first necessary to understand what fun means. That’s easier said than done. It’s a word that people use without really knowing what they mean by it. Fun seems connected to enjoyment, but it also feels different than pleasure—hard things like games and sports can be fun, for example. As a game designer, I’ve thought a lot about the mystery of fun, and here’s what I’ve come up with: Fun is the feeling of finding something new in something familiar. Reaching a new accomplishment in a difficult task at work. Succeeding at an act on the pitch or in the gym that had previously resulted in failure. Doing the same thing already seen before, even, but with small variation.

Fun-size candy bars are fun for this reason. They offer a different way of acquiring, holding, and tasting familiar candy-bar products. They are not as exclusively seasonal as they once were, but it’s still harder (and less culturally acceptable) to have them on hand all the time. Acquiring a large quantity of them, as kids do on Halloween, allows sampling multiple treats in one session of modest gluttony. While still wrapped, they can be contained held or put in the pocket—a secret little treat that’s easy to carry.

But most of all, fun-size candy offers a different experience of recognizable flavors, textures, brand names, and packagings. It affords the mouthfeel of an entire candy all at once. It changes the proportions of chocolate, peanuts, and nougat in a Snickers, or of milk chocolate and crisped rice in a Krackel. It offers the new with the familiar.

The novelty of smallness also explains the cognitive dissonance of Reese’s Peanut Butter Cup singles. Despite being among the best Halloween candy haul, they are also weirdly disappointing. This is because the single cup is the same as the normal package, but halved. The tiny, individually wrapped cups, on the other hand, are fun again, but they are too small to make for effective Halloween booty.

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Handing out full-size bars cheats Halloween guests out of this specific experience of fun, replacing it with the one they already know. Of course, it’s true that finding the house that gives out the full-size bars is fun in a different way. Being that house is also fun. But not gastronomically. Quickly, the pride of being the best house on the block gives way to shame, and the excitement of having the best haul buckles into boredom. When kids return home with the big Snickers or 3 Musketeers, what then? Who cares. They’ve done all this before.

In its pagan origins, Halloween is a day when the ordinary world collides with the world of the spirits, during which both are acknowledged, if only temporarily. To infect it with the confectionery trappings of ordinary life is to spoil the day’s purpose. If you’ve provisioned your basket this year with indulgent, full-size bars, it’s not too late to turn back. Return them to the pantry. Save them for lunches or afternoon snacks. Get some fun-size bars, and help your neighborhood find a tiny novelty in a sea of the familiar.