A viral tweet about picking a seat on New York’s subway prompted a spirited debate over which spot is prized.
It is a subconscious decision that New Yorkers face every day: entering a subway train and making a split-second judgment about which seat to grab.
The choice is primal and depends on a series of calculations, including the length of your trip and the body language of the people seated nearby.
Most riders may not have realized that they had a preference until Gabriel Bautista, a college student from the Bronx, posted a photo and a simple question on Twitter on New Year’s Eve: “All my New Yorkers, which is the best seat?”
In the photo, a group of seats on a D train, in a cascade of orange hues, is labeled with a number, from 1 to 5.
A fiery debate soon erupted. The seat next to the door (No. 1), some proclaimed. The one by the window tucked safely out of harm’s way (No. 4). Definitely not the middle seat (No. 2), everyone agreed.
“Anyone who doesn’t say 1 should be arrested by the M.T.A. Police,” the television writer Bess Kalb responded.
Even Andy Byford, the subway’s leader, weighed in, noting that a true gentleman stands.
“I don’t usually use seats when I ride because they are for customers,” Mr. Byford said in a statement on Thursday. “As for choosing the best, that’s like asking a parent to pick a favorite child. Each one is special in its own way.”
The meme quickly spread to other cities like Toronto and Philadelphia, where transit riders debated their own seating options. And it prompted jokes about picking a seat on a Star Trek spacecraft and the set of the television show “Frasier.”
Mayor Bill de Blasio weighed in late on Thursday, speaking for tall people everywhere and shunning the seats with little legroom.
“1-3-2,” he said on Twitter. “4 and 5 don’t exist when you’re 6’6’.”
Michael R. Bloomberg, Mr. de Blasio’s predecessor and a regular subway rider, agreed with Mr. Byford that standing was the best option.
“I always stand,” Mr. Bloomberg posted on Twitter, alongside a photo of him reading a newspaper on the train, although he was committing his own etiquette lapse by blocking the door.
Some New Yorkers wondered how a train could possibly be empty, as the one in Mr. Bautista’s photo is, and whether it was also delayed. (The criticism is fair: Subway trains are late about 20 percent of the time.)
Other riders had more practical concerns.
“Whichever one isn’t inexplicably wet,” the comedian Mike Drucker wrote.
One rider complained that the seat closest to the door could inspire a robbery. “I call that one the snatch and run,” he said of seat No. 1.
Mr. Bautista, 20, said his train was empty on New Year’s Eve because he gets on at the first D stop in the Bronx. He was home for the holidays from Marist College in Poughkeepsie, N.Y.
“I didn’t expect it to blow up the way it did,” he said. “Everyone has their own opinion. I thought everyone was on the same page.”
Mr. Bautista struggled to select a seat on the train on Thursday morning, ultimately choosing the seat near the aisle where he could sit sideways.
“I picked 5 over 3,” he said, “but just by a little bit.”
The train in the photo is an R68 model, which is used on the A, B, D, G, N, Q and W lines, according to the Metropolitan Transportation Authority, the agency that oversees the subway. About 625 of the cars are currently in service.
Other models have different layouts, like the loathed R32 cars, which are among the oldest in the world. Those breakdown-prone cars have a long bench on either side, where riders often exchange perturbed glances over invisible boundaries because seats are not marked.
The subway seat debate started the same day that Mr. Byford, the subway leader, touched off another viral post on Twitter when the official subway account referred to him as “Train Daddy,” a new nickname that has made New Yorkers chuckle.
The subway Twitter account posted photos of Mr. Byford greeting riders on New Year’s Eve and thanking employees for working on the holiday.
“From Train Daddy himself,” the post said. “Have a great night and get home safely! Mind the gap.”
The nickname came from stickers that had been posted around the city with a photo of Mr. Byford’s smiling face next to the tagline: “Train Daddy Loves You Very Much.”
Mr. Byford, a cheerful British native, has become a bit of a cult figure in New York as he has worked to improve subway service over the last two years.
“He’s bemused that it’s caught on,” Tim Minton, an M.T.A. spokesman, said of the nickname. “He’s pleased about what it says about perceptions that he cares because he does.”