I journal my epiphanies because I always forget them and fall back into the same miserable cycles that got me where I am today
Observations of my day, plans for the week and future, book/game/movie reviews, spellcraft, all the usual things
It relaxes and focuses me. Sometimes when something bothers me I can't get it out of my head, so I put it in my journal to free myself from thinking about it. There's a finality to writing down some thoughts