It is easy to treat Catholicism (or any faith) as a pagan would. For example, we think that if we complete a novena God has to necessarily grant our wishes or if we wear a particular medal we will always win. Our friends tell us that faith can move mountains, and so it can; but we cannot point out a particular mountain and pray to make it move.
Rather God points our mountain to us and tells us to have faith in order to move it. We do not choose our mountain ourselves, but fret not for the mountain God points to us will always be according to who we are, i.e. our talents and interests. We can choose a different mountain, and perhaps through our own efforts we can move it a little; but if we truly wish to make a miracle, then we should stick to the mountain God has chosen for us and move it with our faith.