39. How can a person maintain positivity always?

My simply formula is: when I get a negative thought, feel offended or angry, I begin to think who will suffer out of the manifestation of my negative thinking? Every time, I realize that I will be the sufferer and not the other person. So, if I will be the sufferer then why should I harm myself? All negative thoughts only make us suffer – so why should we indulge in it. This idea keeps my positive thinking alive.