One of the most divisive issues today which gets many Singaporeans worked up has to do with the number of foreign workers here.
It's an evergreen topic not just in online forums, but also in the equally noisy world of coffee shops and dinner parties.
Foreigners take the rap for many things that people are unhappy with - overcrowded buses and trains, sky-high property prices, litter in public places, crime and, yes, even fatal road accidents.
This public unhappiness over immigration isn't by itself surprising - it's a hot topic in many places worldwide, especially in Australia, Europe and the United States, and many governments have had to deal with the political fallout from too liberal an immigration policy. Singapore is thus not unique in this respect.
What's unusual here is the extent of the angst even among seemingly unaffected Singaporeans.
This point though is often missed by those who support the policy and who believe that the dissenters are just a small group who are anti-government to begin with and who are responsible for fanning the anti-foreigner sentiment, especially online.
This is a grave mistake and gets in the way of Singapore arriving at a healthy consensus on what the right approach is to this issue.
Yes, the hatred and vitriol of the anti-foreign camp found in cyberspace should be rightly condemned. But this group isn't the one that needs the most attention.
In fact, it isn't just the anti-establishment camp that is concerned about the problems posed by an overly large number of immigrants.
Want to know when it was first raised as a national issue?
Here is an excerpt from a speech made - but I won't tell you in which year until after you've read it: "But, mind you, there still has to be the road sweeper - the chap has got to collect your garbage.
"We have to mechanise because our young men, having been to school, they don't want to do that.
"So, we now have work-permit holders to do it. And after a while, there is a limit.
"You see the worksite - 60 to 70 per cent are non-Singapore workers. They work harder, they take greater risks.
"What they earn here is two to three times what they earn in their own country. But we carry a social load.
"They dirty the place, they were not brought up in our schools, they litter. It's a problem.
"And if you take too many, then instead of our values being superimposed on them, they will bring us down to their values because it's easier to be untidy, scruffy, dirty, anti-social than to be disciplined, well-behaved and a good citizen."
The year was 1971, more than 40 years ago, and it was in a speech by then Prime Minister Lee Kuan Yew at the National Day Rally. It could have been said just last month by the present PM and still sounded as relevant.
And the point about too many foreigners affecting the values of this place wasn't just a one-off passing mention of a peripheral issue which was soon forgotten.
Mr Lee was to raise it again eight years later in 1979 on the same National Day Rally stage.
This was what he said:
"Let me tell you the risks involved in carrying on as before. Last year, we had a record influx of work-permit holders, over 20,000.
"At this rate, we can safely and accurately forecast further input of 20,000, perhaps, 25,000 work-permit holders for 1980. In five years, you will have 120,000, in 10 years, a quarter million.
"Is it bearable? Maybe if they were from our traditional sources: with Malaysians there are minimal cultural and language problems. Last year, however, because there were not enough Malaysians, we started to move further afield and took work-permit holders from Thailand, from Sri Lanka, from India, from Bangladesh.
"They are good workers. They are hungry, they are lean, they are keen... But I have a responsibility to you. In 10 years, can we digest so many? There will be cultural, linguistic, social and political problems."
Well, those cultural, linguistic, social and political problems have now come to roost, 40 years on.
I have to say when I first came across those two passages I held my breath. I knew Mr Lee had the ability to look beyond the horizon and spot potential problems, but I think even he would be surprised by the accuracy of his prediction.
At the root of the public disquiet is a very basic human fear of being displaced, outrun, undone, outsmarted, and many other things that fellow human beings sometimes do to one another, especially if the strangers are from another tribe who have suddenly appeared at your door.
This anxiety about being displaced in one's own home is a deep-seated one that goes far beyond the occasional gripes about loud-mouthed or anti-social foreigners, and it has to be recognised and acknowledged before any meaningful conversation and resolution of the issue can take place.
The problem is compounded because the experience so far has not been a pleasant one, especially over the last five years when the country's infrastructure - the public transport system, housing, hospitals, etc - was found wanting in the face of the large influx of foreigners. Singaporeans were literally displaced and crowded out as a result.
This lack of proper planning was most unfortunate and was the worst possible outcome for the successful implementation of the policy. It made public acceptance much more difficult.
But infrastructure can be expanded and improved - new MRT lines built and housing stock increased - and in time, it should become less of an issue.
Not so easy to resolve is the issue of values and identity which Mr Lee raised, and the cultural and social problems that he mentioned.
It has to do with valuing the Singapore we call home and which we want to make in our own image and not have it shaped by outsiders who have had nothing to do with our past and our heritage.
This then is at the heart of the complaints Singaporeans have whenever they cite the loud ways of some foreigners, or that they only want to speak their own language and keep to themselves.
The problem is especially acute today because of the large numbers of first-generation immigrants with their very different ways. Over time, when their children grow up here and become assimilated in the local culture, it may become less of an issue.
But now, when many Singaporeans feel the texture of their home is changing too quickly, their anxieties need to be managed and soothed.
There is one reality though which needs to be recognised, and this is that how one feels about this issue partly depends on one's own circumstances.
Successful Singaporeans who have made it and are secure about their future will not feel as threatened by foreigners in their midst. This group includes political leaders and people in business, even more so if they are employers of foreign workers.
The large majority of Singaporeans in the heartlands, who worry about their job security and the future prospects of their children, will have a completely different perspective, and will be much less sympathetic to the argument that Singapore needs these foreigners to grow and prosper.
Policymakers and political leaders have to bear this in mind and try harder to understand the mindset of this large group of Singaporeans who feel threatened. It is a real and deep-seated fear that has to be addressed.
In fact, today's immigrants are far more threatening to this group of Singaporeans than when Mr Lee spoke about it in 1971. Then, they were mainly low-skilled foreign labour being imported into Singapore - the road sweepers, shipyard and construction workers.
Today, there are large numbers of high-end immigrants entering the country, many from China and India. They are no longer the "untidy, scruffy, dirty" lot Mr Lee referred to.
Instead, they are better educated, more hard-working and driven, and better able to compete against professional Singaporeans in many areas of work. And they compete not just for jobs but also for scarce resources such as private property and certificates of entitlement to buy cars.
High-end immigration is infinitely more threatening to the local population than low-end labour, and explains a great deal of the angst and anxiety felt by Singaporeans, including those in the professional class.
Recognising this is a critical part of the exercise to get Singaporeans to accept them in larger numbers.
There is no doubt that continuing to attract immigrants to supplement the local workforce will be important for Singapore to become a vibrant city able to create better jobs and provide greater opportunities to its citizens to do well.
The right mix of immigrants with the requisite skills and attitudes will add to our diversity and make Singapore society stronger and better able to meet the challenges of a globalised world.
But the Government needs to understand the concerns of citizens much better, and at a deeper level than it has.
Failure to do so will make the problem much harder to resolve.