Positive Psychology is almost a two decade old science of well-being (launched officially in 1999 or so by Martin Seligman and others) and there are skeptics who are curious about the "simplicity" of an empirical science which asks people to adopt new interesting habits and to write gratitude note. There are many positive psychology practitioners who vouch for writing a gratitude note while some hold even habits like Masturbation to be aiding in human flourishing.
Writing Gratitude journal is of course a fantastic activity. One may write down thoughts or ideas that brightened up the day. On the other hand, I am also a fan of "ranting" journal where one can release pent up emotions on things that did not go well, "Yes, I did not get a call from that recruiter and I feel really really pissed". Perhaps you could place two journals side by side and take up this challenge - Today for every one negative rant, I would write one positive gratitude note. And you would appreciate the gratitude note better while acknowledging your negative emotions. If you are a Psychologist and you are reading this short blog, you may perhaps encourage your clients or students to take up this challenge.
Sandeep is a Positive Psychology practitioner who has been one of the pioneers in introducing Positive psychology in India in 2010. He facilitates workshops and trainings in the area of Positive Psychology and Appreciative Inquiry. He also certifies individuals to become Positive Psychology Coach. Reach out to him at this link