One of the core practices of Yoga is vairagya, non-attachment. One practicing vairagya is able to enjoy the things of the world, like a guest is able to enjoy the things in someone's home, without claiming ownership of them. The more we can let go of our clinging to things, the more quiet, stable and happy our mind can become.
So how do we cultivate vairagya? One way is to practice selfless generosity. When we are generous to those we love and wish to help, there is still something in it for us because we have an ego identification with them. It's a if they are part of us in a way.
Far stronger is when we give to those with whom we have no relationship, where we expect nothing in return. It is especially this second kind of generosity, selfless giving, that diminishes attachment. In addition, generosity brings a wonderful feeling of love into the heart, and is very helpful to others.
Here's a lovely story about how one woman's selfless generosity engendered gratitude in another. Enjoy.