Decked out in a pink and white cheongsam with matching hat and shoes, the old lady looked sad as she pushed a trolley overflowing with plastic bags onto the MTR at Admiralty.

At the next stop, 40 or more young people filled the carriage not just with their matching red polo shirts but with song, the group breaking into a choral number. Some of the crowd smiled and clapped along (I later discovered it was a visiting Christian group from Puerto Rico).

Enough of Hong Kong’s mobile phone zombie menaces to society

It’s rare in Hong Kong to see public displays of affection or emotion, let alone an impromptu song on a train, so while I was happy to get caught up in the moment, it was depressing to watch the reaction of commuters that early Saturday evening. Instead of embracing the live show unfolding before of them, most disengaged, preferring to bury their heads in their phones to crush candy or message their mates. What was uplifting, however, was watching that elderly lady sitting opposite me, with a feather in her cap, break into a smile.

Having shared the video on the SCMP Facebook page, I was further disheartened by some of the readers’ comments as they vented their anger over the short clip: “So noisy and annoying”, read one. “They should have been fined for disturbing the peace”, said another; others said MTR staff should have thrown them off the train.

Earlier this year the World Happiness Report revealed that Hong Kong had dropped three places to 75th, for happiness among the 156 countries and territories surveyed. It was the city’s lowest ranking yet in the United Nations survey.

I’m pretty sure that lady in pink could give those haters and train phone zombies a lesson or two in how to smile.