EPISODES of anti-social behaviour by groups of young people in Belfast at the weekend will be of concern to many in the immediate areas and beyond.
It must be emphasised that the vast majority of teenagers contribute positively to their communities, through school, sport, voluntary work and other activities.
However, the disturbances at Falls Park in particular clearly went well beyond the high spirits to be expected when young people meet.
Not only were police officers attacked, but bottles and stones were also thrown at passing cars.
Police said there were no reports of any damage to vehicles, which under the circumstances appears to be highly fortunate; it is obvious just how dangerous and irresponsible it is to attack a moving car, which could cause damage, injury or even death if the driver lost control.
Alcohol consumption played a role in the trouble, with many of those involved described by police as "young teenagers".
As well as the drain on PSNI resources, there will have been a financial cost to the council and others involved in the clean-up operation.
Other costs, however, are more difficult to calculate. Part of the price paid for such appalling behaviour is an impairment in residents' enjoyment of their homes.
People also have a right to enjoy using public amenities, particularly playgrounds for young children; the possibility of encountering anti-social behaviour will only deter those who want to use parks for family recreation.
One particularly alarming aspect to emerge following the weekend mayhem is the suggestion that groups of young people from across Belfast are using social media to arrange meetings in order to stage fights.
SDLP councillor Tim Attwood confirmed it was "a problem across the city", as further disturbances at Carlisle Circus and Girdwood in north Belfast on Sunday demonstrated.
Sinn Féin councillor Steven Corr said that in some cases, the Glider bus route was facilitating the fights.
"We're finding these fights are happening in parks along the Glider route, here in the Falls and Dunville and Colin, and over in east Belfast as well," he said; this is surely not how Translink envisaged its new service should be used to connect different parts of Belfast.
While the police, council, schools, community groups, youth clubs and others can make a contribution to addressing youth anti-social behaviour and its causes, parents and guardians can have the greatest influence.
As the police pointed out, parents need "to take responsibility for their young people" and to know where their children are, and what they are doing.
They should also explain to their children the consequences of being arrested for anti-social behaviour - and how a conviction could damage opportunities for travel, study or work.
