If you feel like a wierdo while doing this, you can take some comfort in the fact that it is endorsed by one of the most reputable psychologists in the world (Seligman) and that is has been empirically validated as increasing happiness and reducing depression (https://www.ncbi.nlm.nih.gov/pubmed/16045394)
I agree it can feel like a strange thing to do, but in my personal experience the effects are amazing, not only on the person you write to, but also on yourself.
I agree it can feel like a strange thing to do, but in my personal experience the effects are amazing, not only on the person you write to, but also on yourself.