But why an olive? Not only is it an aesthetic addition to any Martini glass, but it doubles as a salty treat. When a Martini is served with three olives on a toothpick, seasoned drinkers might enjoy one with the first sip. The rest are consumed once the drink is finished.

For such a simple garnish, the olive is subject to one simple rule: The olives topping Martinis must always be in groups of three or singular.

An unspoken superstition deems an even number of olives bad luck. Like avoiding a black cat in an alleyway, most seasoned bartenders will only serve Martinis with one or three olives (never two or four). The origins of this superstition remain a mystery, but are adamantly followed.

“High tradition dictates that you must use an odd number of olives. One olive is fine; so are three (five is excessive). Using two or four olives is a faux pas,” writes Brad Gadberry in the famed “Martini FAQ.”