Great idea! I made a remember-mode template for emacs so I can store happy thoughts whenever they occur.
If you use org-mode and remember-mode you can add this template to your org-remember-templates: ("Happy Thought" ?h "* %U %?" "~/happy.org" "Happy Thoughts")
Doing so made me happy, so I added it to the file, which in-turn produced happiness. Ahhh, recursive happiness.