Ever since I was in the fourth grade, I’ve kept some form of a diary/journal. (Random fact: A “diary” is something you write in every day. A “journal” is something you write in less often.) Those first entries from my nine-year-old self were awkward, and talked more about the boring minutiae of every day than anything of substance. They were only about half a page long, and I’d usually draw some kind of random “artwork” in the margins.
In high school, keeping a diary turned into an addiction. I always had a notebook with me where I wrote down whatever randomness happened to pass through my brain. If I didn’t have the notebook, I’d write on random sheets of paper and keep them folded into a separate compartment of my backpack that I reserved specifically for those sheets.
In college, I wrote in LiveJournal (which I no longer have). I would write pages upon pages of nothing but immature ranting, and to some degree, writing online was easier than it was by hand. Plus, everything was completely private. I didn’t have to worry about someone digging up my journal and reading it.
Now, I write in a paper journal, and sometimes it’s ranting, but most of the time, it’s me trying to make sense of things that are going on in my life. I treat this journal like the Morning Pages, in which you’re supposed to write first thing in the morning about whatever you like without worrying whether it’s grammatically correct or even makes much sense.
Some people will tell you that writing in a diary or journal can help your fiction writing skills. Others will tell you to forget about it, and focus solely on fiction writing if you want to improve those skills. I think that a diary can definitely help you. Some scenes from real life might make great fiction. Sometimes you’ll write about people who can become powerful characters.
But all in all, I see a diary/journal as therapy. It’s a constructive way to keep your feelings under control and to keep worries from eating away at you.