It's infuriating when you pay a vending machine for a snack only to watch it get stuck and not drop. Choose a properly loaded snack, however, and you won't lose your money.
Reddit user DankoJones84, who is a snack and drink vendor, says that items are supposed to be loaded in the vending machine with the bottom corners in front of (through) the spiral, but sometimes the person fills the machine incorrectly.
In the image above, the Elfin Crackers and the Baked Cheetos on the far right are more likely to get stuck, since the spiral probably won't rotate enough to drop the item. In other words, if you see the spiral as a full circle instead of a partial one, don't choose that item.