Usually we find it difficult to control our mind. It seems as if our mind is like a balloon in the wind - blown here and there by external circumstances. If things go well, our mind is happy, but if they go badly, it immediately becomes unhappy. For example, if we get what we want, such as a new possession, a new position or a new partner, we become excited and cling to them tightly. However, since we cannot have everything we want, and since we will inevitably be separated from the friends, position and possessions we currently enjoy, this mental stickiness, or attachment, serves only to cause us pain. On the other hand, if we do not get what we want, or if we lose something that we like, we become despondent or irritated. For example, if we are forced to work with a colleague whom we dislike, we will probably become irritated and feel aggrieved, with the result that we will be unable to work with him or her efficiently and our time at work will become stressful and unrewarding. Such fluctuations of mood arise because we are too closely involved in the external situation. We are like a child making a sandcastle who is excited when it is first made, but who becomes upset when it is destroyed by the incoming tide. By training in meditation, we create an inner space and clarity that enables us to control our mind regardless of the external circumstances. Gradually we develop mental equilibrium, a balanced mind that is happy all the time, rather than an unbalanced mind that oscillates between the extremes of excitement and despondency. If we train in meditation systematically, eventually we will be able to eradicate from our mind the delusions that are the causes of all our problems and suffering. In this way, we will come to experience the supreme permanent inner peace of nirvana. Then, day and night, in life after life, we will experience only peace and happiness.

Geshe Kelsang Gyatso, How to Transform Your Life