The youngsters are often quite arrogant and rude when Marcia Aw first meets them. They don't need her help; they're just fine, thank you.
But when they get involved in the programmes of the Changing Young Lives Foundation, of which Ms Aw is executive director, the defences gradually come down and what often emerge are young, smartly turned out people ready to take on the challenges of life.
The foundation is one of 27 beneficiary charities of this year's Operation Santa Claus fund-raising campaign, co-organised by RTHK and the South China Morning Post.
The teenagers have fun through a scheme comprising basketball and social work the foundation runs. And through it, they learn the tools of giving and receiving that strengthen their chances of a successful and fulfilling future.
The foundation was part of the worldwide Save the Children network until March, when it broke away to focus on charity work in Hong Kong and on the mainland.
It targets the underprivileged youngsters in Hong Kong, including those from low-income families, single parents and new arrivals, and mainland children.