Whether you love them or hate them, shots aren’t going anywhere. Throwing one back is a communal experience, making these night-out staples a way of bringing people closer. The practice is so common that it can become second nature: A friend thrusts a small glass into your hands, you clink the glasses together, drop them to the table with a satisfying thunk, and down the hatch they go.

Tapping the table with your glass pre-shot is a universal aspect of the age-old ritual. But where exactly did the tradition come from, and why do we continue to tap the table today? Turns out, the answer(s) are just like histories of our favorite classic cocktails: murky, at best. Read on for five of the reasons why people tap the bar before taking a shot.

To pay respect to the bar and the people who work there.

Many drinkers believe that the act of tapping the table shows a level of respect for the establishment and the employees who keep it running. By touching the shot glass to the table, patrons are able to nonverbally show their thanks to the often unseen folks who made the moment possible, such as bar backs, delivery truck drivers, janitors, and so on. As Kirk Estopinal, partner at Cure, Cane & Table, previously told VinePair, tapping the table or bar is especially important if the shot you were provided with came “on the house.”

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To toast to those who are no longer with us.

Another common reason people tap is to pay remembrance to loved ones who are no longer alive. This argument is thought to be rooted in the tradition of “pouring one out,” which actually originated in ancient Egypt. Egyptians were once known to pour a splash of water on the ground as an offering for their dead or a deity, and referred to these offerings as “libations.” The practice was eventually adopted by the ancient Greeks — who typically used wine — and later the Romans. It’s possible that tapping the table is a less messy, less wasteful way of respecting the dead while keeping the same sentiment alive.

To keep things clean.

While some of the main arguments for tapping are rooted in respect, others argue that there is a more health-minded reason behind the tradition. Some sources say the practice stretches back to the 19th and 20th centuries when it was common for bar owners to coat the wood floors with sawdust to make for easy cleanup. Given that there were  sawdust particles constantly flying through the air, it was inevitable that some ended up in glassware, and tapping the glass on the bar was a way of removing the harsh sediment.

To ward off evil spirits.

During the Middle Ages, many in Ireland believed liquor to sometimes contain evil spirits that would occupy and possess the body if consumed. As such, many drinkers took to tapping their glasses on the table to scare away the demons who may have been lingering in their spirits. One legend claims that Aldwyn, a 5th-century Saxon peasant, was the first person to ever do so.

It’s an evolution from beer-drinking contests.

In beer-drinking contests, the aim is obviously to consume as much as possible in a limited amount of time. But chugging beers with an abundance of foam can be a challenge, so many contestants slam their glass on the table before chugging to settle the heads. At the same time, the action and accompanying noise helps judges keep track of when a contestant starts a new glass they should add to the tally. It’s possible that the practice of tapping your shot glass is merely an evolution of this habit.