All the netizen and his girlfriend wanted to do was give up their seats to a mother and a child who appeared to be struggling to keep their balance in the LRT.
As the couple got up, the man tapped the mother on her back from behind to alert her to the vacated seat.
However, a man who is believed to be the woman's husband, started scolding the netizen, repeatedly shouting at him: "No touching! No touching!"
Redditor Alarmed_Letter3707 wrote in the forum that he was taken aback that his good intention was met with such hostility in the incident that took place at about 10.30pm on June 8.
He also wrote that the woman's husband spewed racist remarks including "just because it's okay in your country to touch woman in public does not mean it's okay to do that here in Singapore".
The Redditor explained that he tried to defend himself by saying: "'I just tapped her back to offer my seat and I'm sorry for that."
He added that he could not get over the incident and kept his eye closed as he stood in the LRT while the woman's husband continued to berate him.
Other netizens have consoled the Redditor, assuring him that he did not do anything wrong.
Another Redditor shared that he was once accused of manhandling a guest when he tapped a woman who was about to jump queue.
A commenter advised that the Redditor simply wave or say "excuse me" the next time he gives up his seat for someone else.
"This is Singapore, no good deed goes unpunished," wrote Redditor Alarmed_Letter3707, who thanked fellow Redditors for their input and said he would not stop being gracious despite what happened.
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This article was first published in The New Paper. Permission required for reproduction.