Human desires lead to negative thought such as violence, injustice, intolerance, greed, revenge, etc. Negative thoughts arise when a person reacts to situations. You will constantly have various kinds of experiences in the society in which you live. You will face unpleasant situations and unfavourable experiences. When you react to such situations, you develop negative thought. It is very common to react negatively. In those unpleasant moments, you have to control yourself. You have to develop the habit of self-control. When a sentiment arises in you, someone provokes you and you develop negativity, you have to control yourself. The more you have the spirit of self-control, the more you will be successful in developing your personality. You have to refrain from negative thought, swallow your anger, not take revenge, abstain from provocation. You have to control yourself when you develop negative thought. There is another higher level -- converting negative thought into positive thought. 
The first level is to abstain from developing negative thought. If you are a prepared mind, intellectually aware, understand matters with depth, then you will be able to convert your negative thought into positive thought. This is a high level of personality development. If you only stop yourself from having negative thought, the process of personality development will begin. But you will not develop a high level of personality. You build a high level of personality when you convert negative thought into positive thought. 
       How? If someone provokes you and makes you angry, you develop negative thought. The first level is to drink water if you get angry, so that your anger calms down. If you are standing, sit down. If you are sitting, then lie down. If you are walking, change your direction. If you do this, your anger will subside. This is the first level. The second level is to think that the person who made you angry has done something good. 
What is that? He gave you an opportunity to earn great reward.