Many people, Stoic or otherwise, have fallen in love with the process of journaling in the centuries since Marcus Aurelius, Epictetus and Seneca led the way for us all. They dedicated themselves to journaling for good reason; it works. It clarifies the mind, provides room for quiet, solitary reflection on the days events, gives one a record of their thoughts over time, and most importantly it gives us a way to dissect our behavior to see where we can do better in our lives.
There is much to be said for journaling every day. Clearer thought processes, better quality decision making, deeper sleep and a calmer mind can all be attributed to working out your thoughts with your mind by writing them down.
You don't need to use punctuation, know where a capital goes in a sentence or to be able to perform linguistics of any kind. Nope, just use your hand to let your brain kind of 'dribble' out the end of your fingers. It matters not what it looks like or whether it makes sense. Heck, I rarely even go back to read mine, ha! It's just soooo therapeutic to just scribble out all the 'stuff' inside the brain.