BBC Ireland correspondent
The past still casts a long, dark, inescapable shadow over the peace process in Northern Ireland.
Memories of the troubles are still strong in republican minds
Scratch the surface of the new era in Belfast, and the old divisions are laid bare.
Those differences were on full display at the homecoming parade for the armed services in Belfast city centre.
At the flashpoint area, where loyalist and republicans came within shouting distance of each other, the tensions ran deep.
The military parade through Belfast provided a political - and security - test for the new Northern Ireland. Overall, it passed.
But the tensions on view served as a stark reminder of the underlying problems.
In crude terms, unionists see the British Army as heroes, republicans see them as villains. Peace process or no peace process, those views do not change.
And even though Sinn Fein are now helping to govern Northern Ireland, they still decided to stage a protest against part of the fabric of the state.
But could they not have just ignored the military parade? Turn a blind eye, rather than feed the controversy?
It's a question asked not just by unionists, but some nationalists too.
Sinn Fein's answer was found in detail in the pages of the Irish News newspaper, in an article by senior republican Jim Gibney.
'British and proud'
He wrote: "To expect Sinn Fein to somehow pretend Sunday's march is not happening in a city which has experienced the worst excesses of the British army's occupation is to expect Sinn Fein to reject its raison d'etre.
"If those cheerleaders for the British crown forces want to appreciate how nationalists and republicans feel about Sunday's coat-trailing exercise then they should ask themselves how they would react if the Belfast Brigade of the IRA announced they intended to march their volunteers through the centre of Belfast in tribute to all its members who lost their lives during the war."
Some loyalists say they still feel threatened by republicans
Memories are long in Northern Ireland, and many people find it difficult to forgive or forget. Some don't want to.
"I'm British and I'm proud of it but I still feel under threat from republicans," said one prominent loyalist, as he waved his union flag at the troops marching through Belfast city centre.
Apart from a few scuffles, the event passed off peacefully. There was some sectarian chanting from a small element of the loyalist crowd, and some bottle throwing, but compared to some of the dark days on the streets of Northern Ireland, it was minuscule.
The deaths during the Troubles are catalogued in the book 'Lost Lives'.
It not only lists the names of the victims, but pinpoints those responsible for the killings.
In total, 3,636 deaths are chronicled. According to the book:
• 1,771 deaths were caused by the IRA
• 955 by UDA/UVF
• 309 by the Army
• 52 by the police
The rest of the deaths were attributed to smaller paramilitary groups or individuals.
There are no official figures for the number of people injured, but it runs into the tens of thousands.
Northern Ireland's population is less than two million people so the proportion of those directly affected by violence is high.
There are two ways of looking at those grim statistics. One is to wonder if the wounds in Northern Ireland will ever fully heal?
The other is to marvel at how far the peace process has progressed against such a horrific background.
There are also two ways of looking at Sunday's parade - positively, given the lack of violence; negatively, given the display of tensions.
Ask around the pubs and clubs of Belfast and you'll get opposing views.
Mind you, what do you expect in a divided society?