We've all been guilty of saving a seat for a friend at a cinema or pub but it's a truth universally acknowledged that you shouldn't do it on public transport.
However one Australian woman appears to have done just that, with a passenger accusing her of using a backpack to save a spot next to her on a Sydney train for a friend getting on a later stop.
Yesterday a listener named Jason supplied Australia's The Ray Hadley Morning Show with a photo his wife had snapped on a city to Macarthur train, news.com.au reports.
The journey from Sydney's CBD to Macarthur train station takes over an hour.
The picture shows a packed train carriage with passengers standing in the aisle — except for a seat next to a blonde woman which has a bag resting on it.
Jason told the show while his wife had been "happy to stand" there had been "an elderly lady that really could of used this seat".
"It turns out she was holding the seat for a friend who got on somewhere after the airport while all the other passengers had to stand! Refusing to move her bag for anyone to sit down," he claimed.
Jason said the woman had done this despite the train being "packed due to cancellations and issues going on".
"Someone already had words with her and she's sitting there laughing to herself," he added.
Hadley was quick to condemn the woman's actions, saying she should be "embarrassed" and should "hang your head in shame".
"You're very, very rude," he added.
The woman's actions were further blasted on Facebook where angry comments described her as "disrespectful " and "selfish".
"I would have thrown the bag out the door of the train," one person wrote, while another added: "I would have demanded she move it. You can't do that."
"Ah millenials no respect, no manners and no idea," one comment read.
Last year "heartless" commuters were slammed after a photo of an elderly woman standing on a train went viral.
The photo shows the frail woman hunched over and clinging to the pole in the aisle of the train, while people nearby sit comfortably in their seats.
People were quick to describe the fellow commuters as "heartless", sharing the photo more than 32,000 times on Facebook groups as well as Twitter and Reddit.
However after the photo was widely shared the woman's grandson decided to speak out and correct a few facts.
He sent a statement into Ben Fordham's 2GB radio show, explaining his connection to the woman that the nation had jumped to defend.
"The mature age lady was preparing to disembark at the next station — she's my nanna," the man wrote.
Fordham claimed people may have been "too quick to judge" in this case.
Sydney Trains CEO Howard Collins said pictures "can be deceiving".
"This is an opportunity … to remind people that while we're in our world of texts and headphones, we should just be looking up and checking, is there's someone who could do with your seat?" Collins said.