Moments like these don't just happen. To learn more about what goes into making customers happy, we contacted Danil Nevsky, the founder and CEO of the Indie Bartender Company, an organization that strives to inspire and support fearless and enthusiastic bartenders who want to advance as independent professionals.

He said that being a bartender is like being a discount psychologist plus a pharmacist, morphed into an actor on stage at an improv theatre while being shouted at by waiters, the kitchen staff, the guests, and the owner all at the same time.

"It is like trying to juggle umbrellas using your feet on a rollercoaster in Disneyland Paris," Nevsky told Bored Panda. "Those that end up doing this for a living are definitely into masochism and, if anything, are probably the most caring and educated people you will ever meet."

Nevsky said there is a saying about bartenders that goes like this: "The bartender is the aristocrat of the working class." He doesn't look at the phrase as something pretentious or having anything to do with financial wealth. Instead, he thinks it's about people. "Bartending is the only profession where the entire world comes to [you] in good times and bad. Another expression I really like is, 'A man walks into a bar and discovers the world!'"

Nevsky said there's a lot of types of customers bartenders have to deal with but when it comes to tips, "cougars and gay men [are the best.] Both are generous ... and have a more 'free' approach to spending money and trying out new things."

"For conversations, actors and basically everyone in the arts. [They] love to gossip and are generally all 'starving artists' who spend their entire monthly budget in one weekend. They also have the best stories and will teach you something you'll end up passing onto your kids and parents in order to look cultured."

Nevsky added that baristas and other bartenders are the best to make drinks to since they love to experiment with new flavors or know exactly what they want the moment they sit down. "Some will try to show off and catch you out on your knowledge whilst others will give you honest feedback on your original creations while sharing their own knowledge with you. But all of them will keep you sharp."

Nevsky, who also shares his craft on his Instagram account, has had plenty of memorable encounters with his customers as well. "Some were scary, some were spicy and some were just awkward," he said. "One that springs to mind was with a guest who I was serving for a whole month during a brief stint of working in Beirut a few years back. The man would come in and usually just drink straight whisky but I managed to earn his trust and slowly introduced him to some classic cocktails such as the Manhattan, Boulevardier, and Rob Roy. When he learned that I would be leaving at the end of the month, he told me he works at the airport and that I should let him know when my flight was so he can come and say his goodbyes," the bartender recalled.

As with any job, servers don't just become good. To develop their skills, they need on-the-job training. "If you have to choose between spending money on a bartending course and making money working a shift as a bar-back or a cocktail server, choose to work," Lynnette Marrero, a bartender, mixologist, and a co-founder of the world's first all-female speed bartending competition, 'Speed Rack, told Cosmopolitan.

That being said, certain classes, like the Beverage Alcohol Resource (a well-respected accreditation that teaches you all about spirits), are valuable. But they still aren't the same as real-life practice.

Even though servers aren't athletes, injuries like tennis elbow, tendinitis, and carpal tunnel are all fairly common in bartenders, thanks to mixing heavy shakers above your head all night.

As you can imagine, it's exhausting to work 10-hour shifts on your feet, and your back will ache from frequently bending down to grab ingredients under the bar. Not to mention having to entertain the customers.

"Small adjustments—like wearing comfortable shoes, taking breaks to stretch your muscles, and practicing proper cocktail-shaking form—will help your body in the long run," Marrero advised.

Servers also miss out on parties, Saturday night hangs, and having a normal dating life, since most people schedule plans at the same time they're grinding away.

Marrero, for example, is married to a "daywalker" (what bartenders call people with regular day-time jobs), and said that in the beginning of their relationship, it was very difficult to find time for each other. "Sometimes, you'll have to give up your best shifts to go to someone's wedding, and sometimes you'll have to miss out on something important because you can't take off work."

Marrero said there's nothing more glam than comping your friends' drinks, but bartenders should try not to make it a habit.

"You have to account for those drinks (they get charged to a 'comp tab'), and it also shows that you don't view the bar as a place of business."

Of course, the staff can buy a drink for a return customer to build up a relationship, but the buy-back is not a right—it's a compliment to people who visit you regularly.

At a certain point in the night, the bar gets crazy packed and there's a deep line of people waiting to order drinks.

"Some bartenders might take a quick shot at this point to deal with the stress, but I actually find that this is the best time to get in the zone. Customers might get impatient, but you just give them a little nod to acknowledge that you see them and keep banging out drink orders. Time passes the most quickly when it's busy, and you make the most money on tips," Marrero explained.

When the time came and Nevsky arrived at the airport, an armed soldier with an assault rifle welcomed him. "It was the first time in my life I genuinely thought I was absolutely [screwed] and sent my mom a simple 'I love you' just before I got out of the car. The soldier escorted me to the airport and into the customs clearance area whilst confiscating my luggage. As I sat there alone for what seemed like an eternity, the guest I had been serving all month came in with a giant smile on his face holding coffee and sweets."

Turns out, the guy was the chief of border control at the airport! "My luggage was already checked in, and [he gave me] my boarding pass and a bottle of red wine from his grandfather's vineyard. We talked about cocktails, women, and when will I come back to Lebanon. I got out and didn't even have to get my stuff scanned. The soldier escorted me right to the gate as I boarded first. Everyone around probably thought I was important. But I was just trying to recover from a heart attack."

As you can tell from the pictures (and maybe your personal experience), people reveal to bartenders not only their joys but their sorrows as well. According to one study, bartenders said 16 percent of customers routinely did so. But why?

"First of all, if your cocktail-serving confidant works somewhere you visit frequently, you probably don't view them as a stranger," Wendy L. Patrick, J.D., Ph.D., wrote in Psychology Today. "After all, bartenders are trained (and paid) to engage patrons. If you saddle up to their bar often, they remember what you order, and trust me, they also remember how you tip."

But due to the hectic bar atmosphere, bartenders are actually less capable of addressing their patron's personal problems as compared with other informal help-agents, such as beauticians and lawyers, who traditionally engage clients one-to-one. Bartenders, in contrast, are required to engage multiple customers simultaneously

So the next time you meet your favorite server, let them know that you value their work. Your good words will mean just as much to them as your tip.