Sometimes, of course, this can be artificial and forced. In places of autocratic ilk, with the prime example being North Korea, the people must glory in their ''great leader'' and toe the party line, whatever their true feelings.
But in many other places, national days are times of celebration and, for the most part, fellowship. The United States has Independence Day, and Thanksgiving is another time of widespread unity and celebration.
Australia Day - although the history of Aborigine treatment remains a black mark - for the most part helps nation-building against a background of dignity and focus.
Bastille Day in France is something to behold and, although the United Kingdom has no national day as such, Queen's Birthday has a more prominent role and Northern Ireland, Scotland, England and Wales have St Patrick's, St Andrew's, St George's and St David's days respectively; occasions marked at least positively, even if the degree of observance varies from full-on to hardly at all. New Zealand, of course, has Waitangi Day, commemorating the signing of the Treaty of Waitangi between many of the land's Maori chiefs and the Crown.
With increasing official backing, and particularly in the wake of the famous, or infamous, judicial activism of Justice (later Lord) Cooke in 1987, the Treaty is this country's founding document, a living treasure and the basis of ''partnership'' between two peoples. To others it is an historical compact arising out of a time and a place and a specific need that has, unfortunately, been given a sacred aura, far too much importance and become a divisive source for ongoing grievance and division.
Every year, New Zealand has tension at Waitangi, where activists and politicians meet before the cameras and media, and often there is trouble, with, notably, Prime Minister John Key assaulted in 2008 and Labour leader Helen Clark brought to tears by Titewhai Harawira in 1998 after refusing her permission to speak.
The build-up this year - in particular on Monday this week - has been a shambles, with the unedifying scene of ''warriors'' wrestling and Ms Harawira defying requests to stand aside as the person to escort Mr Key to the Ti Tii marae.
She reportedly bullied her way in yesterday, demanding centre stage.
Ngapuhi elder attempts at compromise failed in the face of her intransigence. Perhaps, it has been suggested, February 6 should be called Titewhai Harawira Day.
Hopefully, ugly or unpleasant scenes will be absent today, so that what should be a time of coming together and respect will not be marred.
It would seem a faint hope. But who could argue that there is enough of an undercurrent of disquiet and unease without the actions of some reinforcing these feelings?Here in the South, Maori commemorations are generally festive, affirmative and relatively small scale. Last year, the Ngai Tahu treaty festival was at the Otakou marae on Otago Peninsula. This year's annual festival is at Akaroa, it being shared around different parts of the South Island in different years.
Almost all New Zealanders, however, will do nothing in particular to ''celebrate'' our nationhood. Apart from treating the day as another public holiday, any wider meaning is largely ignored.
And that is perhaps the biggest shame of all, because this is a nation - problems and all - that is blessed in its land, its people and even its institutions. Unfortunately, there is no end in sight to the annual Waitangi upheaval. It is little wonder that for many New Zealanders the focus and feeling of a ''national'' day is on Anzac Day, the one time when unity is widespread, when dignity is upheld and when New Zealand is one nation.
