When website editor Lao Zhenyu's extended family held its Chinese New Year reunion dinner in Guangzhou this year, two usual faces were missing. His female cousins from Hong Kong declined to make the trip, saying they were not in the mood to celebrate with their mainland brethren.
"The cross-border relationship is becoming worse and worse," said a worried Mr Lao, 36.
Tensions between people on both sides of the border have been on the rise, following recent conflicts over parallel traders, tourists and the Occupy movement.
Over the past month, protesters have organised demonstrations in three border towns in Hong Kong's New Territories, heckling mainland visitors.
On Sunday, 38 demonstrators were arrested in clashes with the police.
The targets are parallel traders buying goods - cheaper and deemed safer than those in the mainland - to sell across the border, annoying local residents who have to contend with suitcase- toting crowds and local shops being driven out by high rents.
Radical activists have largely become the face of the protests, carrying pro-independence banners and abusing mainlanders in general. This has led to a backlash on the other side.
A shrill chorus of voices has arisen on social media, tarring Hong Kongers as "ingrates", calling for mainlanders to "boycott Hong Kong" and the central government to "cut off their water and electricity supply".
In a bid to soothe matters, Chief Executive Leung Chun Ying, visiting Beijing this week, is expected to ask that the travel permit scheme for mainlanders into Hong Kong be reviewed.
Introduced in 2003, it allows residents from 49 mainland cities to enter Hong Kong on individual visas instead of with tour groups.
Starting in 2009, residents of Shenzhen, which borders Hong Kong, were allowed to enter multiple times on one visa.
The fracas is the latest in a spate of conflicts between people who have long shared blood and business ties.
Three years ago, Beijing University academic Kong Qingdong threw a verbal Molotov cocktail into the mix when he called Hong Kongers "running dogs of the British" after a video clip of a local upbraiding mainland tourists for eating on an MTR train went viral.
Some in the city returned the insult; advertisements branded mainlanders as parasitic "locusts".
Unhappiness brewed over competition for resources from university places to hospital beds.
In recent months, the Occupy movement lobbying for greater democracy has also heightened the volatility, with Chinese state media spotlighting the protesters as agitating for "independence" with the help of foreign forces.
Said Mr Lao, who operates a website on Cantonese culture: "For many mainlanders who read just the official media, they are easily misled about what Occupy was about."
He also blames the rise of social media, which he said entrenches prejudices and accelerates the dissemination of sensational information on both sides.
"The anger has been simmering, and now the protests over parallel traders are posing a new breaking point. For people like me with family on both sides of the border, it's a sad state of affairs."
Trying to overcome the bickering, cooler heads on both sides are calling for calm. In Hong Kong, commentator Allan Au noted that the mainlanders in Sha Tin - one of the three towns targeted by protesters - were not parallel traders but genuine tourists.
On Weixin, a platform popular with mainlanders, some pointed out that Hong Kong was not "getting gifts" from the mainland but instead, paying market rates for resources such as water.
"While mired in this hatred, we should be rational and objective in understanding the facts... and start healing the wound between Hong Kong and the mainland," wrote one.