A while ago I wrote an article called: Why Did You Practice That?
It was about a strange experience I had in India with an active meditation. This active meditation was the invention of a European guru. And basically it involved letting go of bad memories. Great premise right.
But the idea was to spend 30 days or more deeply remembering terrible memories... Going really deep into them, screaming, crying, getting it all out.
There was no process of letting go... just immersion in those bad feelings and memories. The problem with the 'get it all out' method is that there is always plenty left, more in there for tomorrow. And constant repetition of the same thing thickens neural pathways.
You get good at what you practice. Practice feeling sad and unhappy and guess what!