Greet others' mothers no more - such was the latest message from the police chief in his appeal against Hongkongers using foul language in public.
"Greeting mothers" is a common Cantonese expression referring to foul language.
"Both the police and ordinary residents should be respectful - respect oneself, respect others, and respect the society of Hong Kong," said police commissioner Andy Tsang Wai-hung.
"Let's imagine a Hong Kong where you greet my mother and I greet yours on the street - what kind of society will it be?
"You cannot do something simply because it's not illegal," Tsang said.
His said this yesterday, about two months after schoolteacher Alpais Lam Wai-sze was recorded swearing at police officers and the video went viral on the internet. Lam swore in English.
She was dissatisfied with the force's "inaction" towards anti-Falun Gong protesters obstructing the religious group's activity on a Mong Kok street.
The online dispute with Lam led to a pro-police rally last month, during which thousands of supporters and detractors of the teacher exchanged insults in Mong Kok.
Commenting on the issue in an interview on Commercial Radio, Tsang called it "natural" for the police force to be unhappy when it was "misunderstood".
He asked the police to remain calm in all situations.
But he rejected allegations that police had a political agenda in arresting protesters, claiming that protesters' methods had turned increasingly radical, if not violent.
Tsang also said he would liaise with the Department of Justice on the updated prosecution policy that regulates the arrest of protesters to see if the police needed to change its practices.