Street violence and sectarian lawlessness send out the wrong message, Northern Ireland's Secretary of State has told teenagers.
Theresa Villiers also said it was depressing that some of those involved in the interface rioting were not born when the first paramilitary ceasefires were called in the early 1990s.
In an address to young people born after the 1998 Good Friday Agreement Ms Villiers said there were still major issues to be tackled if the country is to thrive.
She said: "There are still deep-seated divisions in parts of Northern Ireland society. Whenever sectarian tensions spill over into street violence that's distressing and disruptive for those living in the areas affected which are often the most economically disadvantaged in Northern Ireland.
"And this kind of lawlessness also sends a negative message round the world that does real damage to Northern Ireland's reputation and its ability to compete. And it is depressing that some of those involved in disorder and sectarianism weren't even born when the first ceasefires occurred and the peace process started in earnest."
Earlier this month Ms Villiers was accused of blackmailing local politicians when she said an economic package to help businesses could be withdrawn if the Stormont Executive failed to agree on a shared future.
She added: "Beyond doubt the passing of time won't be sufficient on its own to bridge long-standing sectarian divides. Looking ahead we will need a sustained effort to build a society based on mutual respect for all citizens, regardless of their community background. A society that's free from the blight of sectarianism, intimidation and paramilitary violence and where the rule of law is paramount."
Also at the event at the Metropolitan Arts Centre (MAC) in Belfast to mark the 15th anniversary of the signing of the landmark peace deal were Irish Foreign Minister Eamon Gilmore, business leaders and academics. Teenagers from schools across Northern Ireland were invited to take part in a question and answer session with both politicians.
Mr Gilmore said Belfast had changed almost beyond recognition over the past 15 years.
"The amount of killing and injury which was so much a feature of Northern Ireland life more than 15 years ago - that has changed. Anybody who remembers this city 15 years ago can see the huge ways in which it has improved. But there are still deep divisions. We still have issues. There are too many walls, both physical and in our minds," the minister said.