It's as good as finding a £10 note in your coat pocket — an empty seat on a rush-hour tube. So this morning, spying an empty, uncontested priority seat, you plop yourself down and settle in for the commute, diving into the Metro for Trump's latest gaffe.
A couple of stops go by. Over the top of the paper, you see a woman get on. She smiles at you. 'What a nice cheery person,' you think, smiling back and returning to your paper. 'Today is looking brighter already.'
A few seconds later: a tap on the shoulder from a fellow passenger. "Are you pregnant?" is their ridiculous question.
"Well SHE is."
You slowly follow the finger to the woman who just smiled at you. As you lower your paper, this time you notice she has a massive bump and is clearly pregnant. Trump's gaffe (also massive) was covering the bump.
In a fraction of a second the full gravity of the situation hits you. She was smiling because she wanted your seat.
You left a pregnant woman to stand.
Springing from your position as if stung by a wasp, you stutter out the confused explanation that you hadn't noticed the pregnancy because of the newspaper in front of you. The pregnant woman accepts the excuse graciously.
Your fellow commuters aren't convinced.
"Yeah right, 'the newspaper was in the way'", the whole carriage is thinking.
Retreating to hunch in the corner like a naughty child is all you can do to avoid the accusatory eyes. Once you were comrades, battling the transport network together. Now you're ostracised, cast out by their judging looks.
Men, women, elderly people, teenagers and the odd dog are united in their hatred towards you.
Tube station notice boards will soon feature your mugshot, so you can be named and shamed publicly. Twitter will trend with #SelfishCommuter. You'll have to go into hiding like that dentist who shot Cecil the lion.
There's only one course of action to take. Vowing never to sit in the priority seat again, you jump off the train and wait for the next one. It will contain commuters who are unaware of your unintended yet shameful actions.
You will be reborn as a respectful Londoner.
Have you ever had an awkward moment like this? Confess your shame in the comments.