Be happy

In Harry Potter books, there are these characters called dementors. They are foot soldiers used Voldemort (one who must not be named), Harry's nemesis. 

These dementors suck out all the happiness and good from you. Only way to survive their attack is to remember your happy memories. 

A very good analogy - I feel. The bad thoughts suck out everything from our mind. And we can only defeat them by reminding ourselves of good memories.

Most often we feel we do not have such memories. Which is not true. We do have our share of good memories. But we do not think of them as often as we should. So they are clouded away by our defeats, our regrets and our sadness. 

So let us beat dementors by thinking of good thoughts.