Some people harm others without any provocation. They simply love doing so. It is very strange that we enjoy doing to others what we hate others doing to us. We enjoy hitting others, although we do not want others to hit us. We like telling lies, although we want others to tell us the truth. We are rough to others, although we want them to be nice to us. This duality in our personality is really very perplexing. Some people have a very strong urge to harm others while some may experience the urge only occasionally. Even the best of us sometimes feel like harming others without any reason. This is another dimension of duality that characterizes human beings.
Why do we derive pleasure in harming others? Perhaps, we release our pent-up stress in this manner. When we physically or vocally become violent and hurt others, we feel lighter. Sometimes, we harm ourselves to get rid of the stress, but harming others is obviously a better option which we generally choose.
What can we do to curb our tendency to harm others? We should, perhaps, put ourselves in their position and imagine what our reaction will be if they were to harm us without any reason. Initially, this may be difficult, but gradually, through practice, we should be able to do so and restrain ourselves.
A better remedy, perhaps, is to try and make ourselves more peaceful from within. If we can learn to forget and forgive, if we can learn to accept both good and bad in our lives, we can perhaps be more peaceful from within. The force which prompts us to harm others will then be under some check even if it does not vanish altogether.