The same way we exercise our bodies we have to keep our minds healthy. We must train ourselves to get rid of the negative emotions and unpleasant experiences. Just let it go. Make room for positive thoughts!
So, it is really up to us to observe and train our brains, therefore our direct our thoughts in the correct direction – meditation, mindfulness helps us focus on what is important and relevant – leave all the bad stuff ( negative thoughts, negative people, voluntary and involuntary bad emotions, etc) as far away as possible…delete them really.