The Dalai Lama

On suffering from the book The Art of Happiness

"We can see that there are many ways in which we actively contribute to our own experience of mental unrest and suffering. Although, in general, mental and emotional afflictions themselves can come naturally, often it is our own reinforcement of those negative emotions that makes them so much worse. For instance when we have anger or hatred towards a person, there is less likelihood of its developing to a very intense degree if we leave it unattended. However, if we think about the projected injustices done to us, the ways in which we have been unfairly treated, and we keep thinking about them over and over, then that feeds the hatred. It makes the hatred very powerful and intense. Of course, the same can apply to when we have an attatchment towards a particular person; we can feed that by thinking about how beautiful he or she is, and as we keep thinking about the projected qualities that we see in the person, the attatchment becomes more and more intense. But this shows how through constant familiarity and thinking, we ourselves make our emotions more intense and powerful."

"We also often add to our pain and suffering by being overly sensitive, overly reacting to minor things, and sometimes taking things too personally......"

Buddhism