Why do we complain of not being heard?
Are we convinced that "we do not know how to pray as we ought"? Are we asking God for "what is good for us"? Our Father knows what we need before we ask him, but he awaits our petition because the dignity of his children lies in their freedom. We must pray, then, with his Spirit of freedom, to be able truly to know what he wants.
Source: Catechism of the Catholic Church (Vatican.va)