It is not enough simply to wish that love and compassion should increase in us. We need to make a sustained effort, again and again, to cultivate the positive aspects within us - and the key here is constant familiarity. The nature of human thoughts and emotions is such that the more you engage in them, the more you consciously develop them, the more powerful they become.

Transforming the mind: teachings on generating compassion (ed. Thorsons Pub, 2000)