Hong Kong and Singapore are rivals on many fronts. The two former British colonies compete for everything from tourist dollars to stockmarket listings and the right to host the regional headquarters of international corporations.
Politically, many Hongkongers deride Singaporeans for their weak political freedoms, while some in Singapore argue that Hongkongers' love of protesting goes too far.
But the two sides are locked in a new battle - perhaps a surprising twist in this ago-old contest - and it indicates that the two have rather more in common than they would care to admit.
Despite their wealth - Singapore and Hong Kong rank third and seventh on per capita GDP according to the World Bank - the two cities are among the least happy territories in the world, according to a Gallup poll released last month.
Singapore is way ahead in the race to be Asia's most miserable place, ranking rock bottom in the poll of 148 nations and territories, with just 46 per cent of those polled expressing positive feelings. Hong Kong came in 73rd, with 69 per cent of respondents expressing "happiness".
Panama and Paraguay topped the poll, with 85 per cent of the respondents reporting positive emotions. China, the United States, Chile, Sweden and Switzerland tied at 33rd place, despite the wide wealth disparity in these countries.
Happiness, after all, is a subjective sense of well-being; different cultures have different interpretations of it.
"The Gallup poll tries to standardise happiness between different places. Therefore, the poll uses positive emotions as a reference," Tso Kwok-chu, a psychiatrist who runs a clinic in Hong Kong, explained.
According to the World Bank, Singapore had a per capita GDP of US$60,688 as of December 30, 2012, while Hong Kong trailed at US$50,551. Of the two happiest countries in the poll, Panama's GDP per person was US$15,589 and Paraguay's was US$5,501 - about one-tenth of Hong Kong's.
"Singaporeans, while absolutely well off, are relatively unhappy. The survey is on to something real," said Yeoh Lam Keong, vice-president of the Economic Society of Singapore, a non-profit organisation of economists.
Alan Lo Tzee-cheng, 45, a teacher at the International College Hong Kong who moved to the city from Australia four years ago, said many Hong Kong people were too focused on achieving material success, which made them unhappy.
"I can understand why so many people say they're unhappy in Hong Kong. I travel throughout [the city] during the course of my work and see a great cross-section of people. A lot of problems start with the fact that the culture and society here is very focused on success that's based on, essentially, money," Lo said.
"Money and competition about making more money than others penetrate all parts of people's lives. Their education, the way they raise their children, what they eat. Even to go shopping can be an emotional trial. Lots of luxury goods are so priced out of people's range that it builds up jealousy and envy. People become quite negative. I think that's the heart of it."
As a result, the people in Hong Kong and Singapore find themselves constantly buried in an avalanche of work, leaving them emotionally insecure and fragile.
Singaporeans have one of the worst work-life balances in the world, as they work some of the longest hours globally, explained Yeoh, a senior adjunct fellow of the Institute of Policy Studies, a Singapore think tank. "They are overstressed and do not have enough time for family and recreation."
An International Labour Organisation report in 2010 found that Singaporeans put in the longest hours at work. While the report did not specify exact numbers, the Ministry of Manpower in Singapore put the average at 45.9 hours per week. Hong Kong follows closely, with 44.5 hours per week according to government statistics.
There are no comparable statistics from Panama and Paraguay. In Panama, 50-hour workweeks are allowed for two months in a year for manufacturing ventures during the peak season. In Paraguay, the standard working hours for civil servants is around six to seven hours a day.
Wealth does not necessarily guarantee a good quality of life. The average living space in Hong Kong is only 12 square metres per person - one of the smallest in the world. Singapore ranks much better at 25 square metres per person. However, despite its reputation for having world-class public housing, education and health care, these are becoming increasingly unaffordable for a significant segment of Singaporean society, according to Yeoh.
Overcrowding and wage stagnation due to immigration have generated huge negative social challenges for low and middle-income Singaporeans, Yeoh added. "Income inequality has risen to high levels. Most studies show high income inequality leads to poor social well-being, reducing social mobility."
As Chua Kheng Kok, Asia Pacific president of Mary Kay, an American cosmetics company, remarked: "The polarity of wealth in Singapore has resulted in the rich becoming happier and the common people become unhappier. I find Singaporeans more envious of each other and therefore less happy."
The increasing wealth gap is hardly unique to Singapore.
In Hong Kong, government figures show that the median salary of Hong Kong's top 10 per cent of earners is HK$88,800 a month, more than 26 times that of the poorest 10 per cent.
Overall, one in six people, struggled with poverty in the second quarter of last year - a shocking figure given Hong Kong's reputation as one of the most affluent societies in the world.
And the problem is not just the disparity in wealth distribution, but also people's mentality towards it.
Jacqueline Tong Tze-ling, 24, an engineering consultant for an international firm who was raised in Canada and lives in Hong Kong, says Hongkongers are too intense and competitive.
"The main causes of unhappiness in Hong Kong are financial, and that's just how the society is set up. Everyone needs to compete, and it starts really early. Preschoolers already need to develop a portfolio. That's ridiculous. When I was in preschool [in Vancouver], I was happy and blowing bubbles," she said.
"People make their kids grow up too fast here. They don't get time to explore and enjoy the things they want to do … basically people trade their health in order to gain wealth in Hong Kong. That's the norm."
Alvin Tan Sheng Hui, a Singaporean working in Hong Kong, put the dilemma simply: "We in Hong Kong and Singapore have a lot to be thankful [for] and we forget that. We have more than we need, which also engenders envy and dissatisfaction. We want more, yet we thank less."
In both Hong Kong and Singapore, the key determinants of happiness are money, career and family, said Alvin Tan, an executive director at a leading investment bank.
"Singaporeans are generally positive fellows, though the pursuit of the 5Cs is now in question - whether it really brings true happiness," said Kelven Tan, a Singaporean businessman. The 5 Cs is a Singaporean acronym for the symbols of material success: car, cash, credit card, condominium and club membership. Tan said he had become happier after moving to Canada from Singapore several years ago.
"I moved because I wanted my family to know there is more in life than earning money, more to learning than scoring As to get good jobs, to learn the truths themselves," Tan explained.
Lee Kwok Cheong, CEO of SIM Global Education, the largest provider of private education in Singapore, said: "We [Singaporeans] have the paradox of being happy and unhappy at the same time.
"Singaporeans are on the whole happy. We appreciate how far Singapore has developed and how we have done better than most countries. We like to boast we are No1 in this and that.
"At the same time, we focus on where we have fallen short, and compare ourselves against a very high standard. This is partly due to our government reminding the population we would lose everything if we drop the ball. This insecurity, plus the pressure of living in a crowded city, cause us to complain."
In Hong Kong, property is the one thing that makes or breaks a person's fortune - and largely decides if he is happy or not.
Hong Kong residents who profited from earlier waves of property inflation were happier than those who did not, said Lee, a Hongkonger who has lived in Singapore for many years.
Tong, the engineering consultant, agrees. "It is very tough for young people to establish themselves in Hong Kong. They really can't afford to support themselves. Housing is a really big deal. They end up living with their parents even after they get married," she said.
"So you end up with generations of people living together, so no one has privacy or time for themselves at all because they're crammed in a small space."
Singaporeans generally do not wear their emotions on their sleeves and open up to strangers, unlike people from Malaysia or the Philippines, said Raju Chellam, South Asia and Korea head of cloud practice for Dell Computers.
"But the reality is different. Singaporeans care about their country, family, neighbourhood and people who have been mistreated. Since Singapore is hyper-efficient, there is little to complain about, compared to many countries," said Chellam, who was born in India and has lived in Singapore for 20 years.
A Singaporean lawyer working in Hong Kong said he felt happier here, enjoying the freedom and vibrancy of the city.
"People are less angry and more comfortable with themselves. … Everybody has a different point of view and is not afraid to express their individuality. The transportation system works well. Things are not overpriced except housing.
"You don't feel the government is taking everything and leaving you the crumbs. When you walk around the streets, you always find new things to discover. The city is always interesting, alive and surprising," he said.
However, not everyone is seeing the benefits.
The proportion of poor people is increasing in Hong Kong, says Tso, the psychiatrist. Many young Hongkongers with university degrees born after 1980 have high qualifications, but low income. "These young people have become frustrated and helpless."
Tso has a front-row seat to Hong Kong's high-pressure culture and the toll it takes on citizens. "Hong Kong people are under great stress. There is great demand for mental health services in Hong Kong nowadays."
Chua, of Mary Kay, offers a solution: wherever one lives, the key to happiness is to count one's blessings and to look on the bright side of things.
Measuring happiness - Hong Kong vs Singapore
Per capita GDP: US$50,551
Nicknames: Asia's World City, The Big Lychee
Reasons to be cheerful: Spectacular views of mountains and the harbour, impeccable public transport, ultra-low taxes
Reasons to be gloomy: Pollution, overcrowding, astronomical property prices
Per capita GDP: US$60,688
Nicknames: The Lion City, Disneyland with the Death Penalty
Reasons to be cheerful: Obsessive cleanliness, year-round warm weather, mix of cultures and cuisines
Reasons to be gloomy: Limited political freedom, corporal and capital punishment, large-scale immigration
Sources: World Bank, CIA World FactbookTopics: Singapore Hong Kong Happiness