The internet is full of photographs accompanied by increasingly exaggerated stories.
That makes skepticism healthy, especially when a story appears almost too perfect.
In this case, however, the core account is unusually well documented.
The Guardian reported the story through Press Association on October 30, 2015.
ABC News interviewed Douglas directly.
The Irish Times reported the flight, hotel and pub encounters.
CBS covered the viral photograph.
The Independent identified the two men and reported additional details about their trip.
PRX's The World subsequently interviewed Douglas, allowing him to recount the events in his own words.
Those independent reports agree on the central facts.
Douglas boarded a flight bound for Galway and encountered Stirling.
The men looked strikingly similar.
They took a photograph.
They discovered they were staying at the same hotel.
And they later encountered each other again while out in Galway, where they shared a drink.
Some retellings online have embellished the story by presenting the two as virtually identical human copies or implying something mysterious was happening.
There is no evidence of anything supernatural, and "identical" is obviously an exaggeration.
They were simply two unrelated strangers with an unusually strong resemblance who experienced an amusing sequence of coincidences.
The truth is already strange enough.
What If Stirling Had Been in the Correct Seat?
Perhaps the most amusing detail is that the entire story might have unfolded differently because of something as mundane as an airplane seat.
Stirling was sitting in Douglas's assigned place when Douglas arrived.
That forced the two men to interact.
Had they been seated several rows apart, Douglas might have walked onto the aircraft without ever noticing him.
They could have travelled on the same plane, checked into the same hotel and perhaps even visited the same part of Galway without realizing how much they resembled one another.
Instead, a seat mix-up placed them face-to-face.
One tiny disruption transformed an ordinary flight into a story that would be reported internationally.
That is part of what makes the encounter so appealing.
Large events often begin with surprisingly small moments.
A person sits in the wrong seat.
Another person notices.
Someone takes a photograph.
A friend posts it online.
Thousands of people share it.
Within hours, an everyday travel story becomes international news.
From Strangers to Drinking Buddies
The most charming part of the story may be how casually Douglas and Stirling handled the situation.
There was no elaborate attempt to turn their sudden fame into something profound.
They laughed.
They took a selfie.
When they unexpectedly met again, they laughed some more.
Eventually, they had a pint.
Stirling reportedly joked about wanting a quiet weekend away before suddenly finding himself at the center of an internet sensation.
Douglas similarly appeared to enjoy the absurdity of it all.
That reaction is perhaps why the story remains so likable.