The Bartender

"I'm Guinan. I tend bar and I listen."

—Guinan, Star Trek: The Next Generation

Working in a bar is never easy. You have to deal with lowlifes, drunks, soldiers who will harass the female entertainment and some of the clientele with their better armed arsenal, and the average Joe who confesses his life problems to you as you pour him another round. This is the life of The Bartender: he pours a round and just quietly listens and observes the setting.

Unless, of course, he's asked for advice. Just how valuable this advice might be depends on the story, but when you're desperate and maybe a bit drunk, it might seem like a good idea. Expect him to hear "I'll Tell You When I've Had Enough!" pretty often. The real weirdos will be the ones who get Drunk on Milk.

Many bartenders are known only by their nickname. They also often take up the duty of a Quest Giver in any fantasy (or science-fantasy)-themed Tabletop Game.

Examples of The Bartender include:

Anime

Blueno from One Piece took advantage of this as he disguised as one for several years to find any information about an ancient Warship.
- Makino owns a bar in Fuusha village.
Bartender, predictably, is an anime centered around a Bartender, his bar and the stories of its patrons.
Mirajane of Fairy Tail is this for the entire guild.

Comic Books

At the center of the Criminal universe is Gnarly, the ex-boxer who runs The Undertow, a dive bar frequented by crooks, con-men and people who just plain run out of luck. Like most bartenders, he has seen and knows a lot more than he lets on, and is extremely judicious in applying it.
A Nice Guy bartender shows up in one story in Preacher (Comic Book) and ends up helping Tulip's best friend with some sage advise while she's feeling down about her (lack of a) love life. And then, because this is a Garth Ennis comic, we get a hilarious (for us, not for him) story about how he ended up chemically castrated after he got mistaken for a child molester by the police.
Kadies in Sin City usually has waitress Shellie in the role as an earpiece as evident by Dwight's background confessions seen in many stories. Her (and Kadie to a lesser extent) seem to be able to get Marv calmed down, no easy feat.

Film

Cheech Marin's character in Robert Rodriquez's Desperado didn't even have a name. He was just called "Short Bartender."
Danny Trejo tended bar in both From Dusk till Dawn and Anchorman: The Legend of Ron Burgundy. The roles wouldn't be that noticeable if they weren't being played by DANNY FREAKING TREJO!!!
Brian Flanagan (played by Tom Cruise) learns the fine art of bartending from Doug Coughlin (Brian Brown) in Cocktail.
The extremely creepy Lloyd of the extremely creepy Overlook Hotel in The Shining.
Joe in The Sky's the Limit, who is addressed in the movie's Breakaway Pop Hit, "One For My Baby (And One More For The Road)."
In Keeping the Faith, the Framing Device is the priest (name?) "confessing" to The Bartender.
In Bunraku, Woody Harrelson's character is a bartender who goes simply by the name The Bartender.

Literature

Justin Callahan of the Callahans Crosstime Saloon stories by Spider Robinson.
"Mac", who runs MacAnally's in The Dresden Files. MacAnally's is one of few places which is neutral ground for supernaturals, so every non-"vanilla human" in Chicago will drop by sooner or later. He doesn't talk much, though.
Larry Niven's Draco Tavern books are told from the perspective of the human barkeep to an alien Bar of Weirdos.
Aberforth Dumbledore, the barkeep of the Hog's Head in Harry Potter.
The Ship Who Searched by Mercedes Lackey has a scene where the male lead pours out his woes to a bartender and receives some good advice—along with a Lampshade Hanging, as it's revealed that bartenders in this future setting are given formal training in psychological and relationship counselling because of how often they're in scenes like this.
In The Lord of the Rings Barliman Butterbur hands down private letters among some of his customers and shares with them important information. Though he sometimes errs in giving advice, Gandalf trusts him and makes him his deputy Quest Giver.

Live Action TV

Eastenders has The Queen Vic(toria) pub, which is basically the centre of Albert Square. If you run it, you're in charge of the square. Usually, bad things happen to you, too. Several characters fight for the title King/Queen of the Vic.
Sam Malone from Cheers not only tended the bar, he owned it. At least for a while.
- Both Woody Boyd and Ernie "Coach" Pantusso worked as bartenders at the Cheers bar as well.
Al Swearengen from Deadwood tended the bar, when he wasn't being the town's crimelord.
Guinan from Star Trek: The Next Generation, source of the above quote.
- In the original pilot of Star Trek: The Original Series, "The Cage," the Chief Medical Officer, Dr. Boyce, has a drink kit to use when he wants to get a patient of his to open up. As he says "Sometimes a man will tell his bartender things he'd never tell his doctor."
Quark from Star Trek: Deep Space Nine.
Invoked in one episode of The Big Bang Theory. When Sheldon sees Penny working the bar, he expects her to act like the typical bartender, pouring drinks for him to drown his sorrows in and offering him sage advice.
In Life On Mars, Nelson is an oracle nonpareil who may just be the protagonist's subconscious. He's also a Fauxreigner in that he plays up a Jamaican accent so people don't take him too seriously ("Folks just seem happier with the other Nelson"). He turns up again in the very last episode of Ashes to Ashes, which reveals (MAJOR spoilers): that he's more or less the British copper's equivalent of St Peter.

Theatre

Nick, owner of Nick's Pacific Street Saloon, Restaurant, and Entertainment Palace in The Time of Your Life.
Bye Bye Birdie has Charles F. Maude of Maude's Roadside Retreat, Sweet Apple, Ohio.

Western Animation

Moe Szyslak from The Simpsons, voiced by Hank Azaria.
In Bravestarr, Handlebar was the resident bartender in New Texas. He fought more than he listened, though.
Horace, from Family Guy, who is the proprietor of the Drunken Clam in Quahog.

Web Comics

Lampshaded in Everblue.
Crystal of Sluggy Freelance hosts the bizarre cast of the comic in her bar, always ready to comfort them with a smile and a free drink she mixed herself. For your own safety, do NOT try her experimental cocktails.
Darin of Wapsi Square is the wise, almost fatherly variety. Here is his introduction.
Bacchus, the protagonist of Nectar of the Gods is this kind of character, who tends to the bar giving characters advice and serves them a perfect cocktail to soothe their troubles, and practically every other character in the comic is a bartender as well.
Kendrion from Even in Arcadia spends time pouring his rejected heart out to a barmaid who ends up giving him advice.

Web Original

One of That Guy With The Glasses's characters, Dominic, is this. It's not easy for him, because the bar in question is mostly visited by troubled Video Game Characters.

Video Games

The bartenders in the Quest for Glory games are usually of the rough, shady, and not very friendly variety. Probably a member of the Thieves' Guild.
- Pretty much a given, since the Thieves' Guild is under the bar in game 1, in game 2 the bartender is a minion of the most prominent criminal in a corrupt city, and in game 5 the entire bar is owned by that same person; there aren't any taverns in games 3 and 4.
Telma in The Legend of Zelda Twilight Princess, to The Legend of Zelda Majoras Mask's Mr. Barten, the keeper of the Milk Bar in Termina.
A Turian bartender in Mass Effect 2's Dark Star lounge lampshades the advice-giving portion of the Bartender trope; if Shepard attempts to milk him for gossip, he suggests you ask around before commenting that he doesn't get "why humans always ask him that."
- Another lampshade is hung by Aethyta, the Asari bartender on Ilium, who turns out to be a Matriarch. When the character asks what she's doing tending bars, when Matriarchs are supposed to be councilors and figures of wisdom, her reply is, basically, "that's why Matriarchs make the perfect bartender."
  - The third game reveals that she's Liara's father (no, not her "other mother", her father) and was keeping an eye on Liara's intel-broker activities for the other matriarchs. She moves to a bar on the Citadel once the Reaper war starts.
- In Omega, a Batarian bartender tries to poison Shepard, but since this is Shepard, he fails. Shepard then has the option to return to either force the bartender to drink his own poison (Renegade), get a paranoid Turian to shoot him (Paragon) or tell him to scram (also Paragon). He's promptly replaced by a salarian.