(CNN) — Airline Twitter feeds are the digital equivalent of an airport customer service counter.
There is anger. Despair. Grudging acceptance of mildly satisfactory compensation.
The feeds are an endless litany of air travel woes: complaints about surly gate agents, photos of damaged luggage, desperate pleas to hold a gate so a traveler can make their connection.
In an age when customer service takes place in public view -- and one bad response can ricochet around the globe in seconds -- handling customers' emotional baggage in 140 characters or less is no small feat.
With complaints shifting to social media instead of offline help desks, keeping up with requests is the job of specialized teams who work 24/7 to field problems, complaints, questions and even the occasional compliment.
As with other customer service venues, dissatisfaction and impatience tend to dominate customers' tweets. (The exception to this is Delta, whose relentlessly cheerful and oddly flirtatious feed is unusually lacking in negative queries.)
Airlines adopt several personas when it comes to dealing with customers via Twitter. Sometimes they have the calm, soothing presence of a crisis hotline operator:
Or a therapist.
In the face of opposition they can be impressively unhelpful . . .
. . . and resolutely immune to sarcasm.
When praised -- which is rare -- their elation is touching.
"Developing our voice in social media environments is more of an art than a science," says Jennifer Dohm, a spokeswoman for United Airlines.
The company is investing more heavily in social media, Dohm says, as customers increasingly turn to public forums like Facebook or Twitter to seek help and air complaints.
United and other airlines contacted for this story say they aim to respond to all comments and queries that come in via social media channels.
"We don't distinguish between comments," Dohm says. "If a customer reaches out to have a conversation, positive or negative, we're happy to do so."
United found itself on the end of a very public furious tweet in May 2014, when recording artist will.i.am tweeted that he'd been barred from the airline's lounge.
The company later said his ticket didn't grant him access to that particular lounge, but by that time, supportive followers had already piled on.
As in will.i.am's case, representatives often discreetly direct the conversation away from public view, inviting them to directly message them to avoid posting personal information or flight details.
"We encourage our customer service representatives to be conversational, approachable, and that it's OK to have a little fun when appropriate," says Jonathan Pierce, director of social media for American Airlines. "Striking the right tone is about reading the signals in the conversation."
Sometimes, that conversation goes terribly, terribly wrong.
The mother of all airline-related tweet catastrophes occurred on April 14, 2014, when a disgruntled passenger tweeted US Airways about a disrupted spring break trip.
"We don't like to hear this, Alex," US Airways replied. "Please provide feedback to our customer relations team here."
Attached was a pornographic photograph of a woman using a model Boeing 777 for a purpose for which it was not intended.
The tweet was live for 22 minutes, long enough to go viral and inspire countless comebacks. ("Charging $60 to check bags is still the grossest thing US Airways has ever done," TV writer Vanessa Ramos tweeted in response.)
A US Airways representative said at the time that the tweet was an "honest mistake." Someone had earlier tweeted the photo to the airline's account, and in the process of flagging it as inappropriate, an employee inadvertently copied the URL to the passenger's reply.
"We learned lessons from that incident that have enhanced many aspects of our social media operations," was all Pierce would say when asked about the tweet's legacy.
The incident happened in the middle of US Airways's ongoing merger with American Airlines, which now handles both companies' Twitter accounts.
Are there any other notable moments in their social media history? Pierce would rather not say.
"We have many memorable conversations, but as each customer has unique circumstances and requests, would prefer not to call any out."