I am totally one of those people who had diaries with locks on them in my childhood. Have you seen the movie Sisters? With Tina Fey and Amy Poehler? Like many others I'm sure, I was rolling on the floor laughing/snorting along with my mother and sister as we watched the scene where the characters read their childhood diaries aloud - I am definitely the 'Maura' in my family! #craftingheals
Journaling can resemble a diary - thoughts, hopes, dreams, fears. For a long time in college I would journal in the evening before bed, and basically recount the events of the day, and maybe how I felt about them. I can see now that it was part of my meditation practice before I knew what an actual meditation practice looked like. I would put all the noise in my head on the page as words - and then I would literally close the book/day and go to sleep.
These days I take a lot of 'study' notes in my journal. Learning is my true life passion. How wonderful that there are so many things to learn about in this world! I'll read a book and take notes about a certain passage, I'll watch a video and write down quotes, I'll look at a magazine and record the interesting aspects of a photograph. I've toured art galleries and journaled, I've sat on the beach and journaled, I've journaled while on public transit and written 'the guys next to me is reading this over my shoulder...' so that he would turn immediately and awkwardly to look out the window, ha!
Writing my thoughts on a page just comes naturally to me and I am not self-conscious at all about pulling my sketchbook out in public. (I journal AND draw in the same unlined sketchbook.) I would consider myself sensitive, an emotional type, who generally has her shit together, and is proud of that. I would also contribute some of that to my long held habit of journaling.
It's just writing words on a page. Some people like to write more creatively - one of my friends told me she'll write while at the cafe - she'll pick a customer and write a presumptive story about where that person is going or what they've already encountered in their day. Make believe. Fiction. I've also followed along with creative writing prompts myself, from sites such as this. Occasionally I'll write poetically on the page, but for me it's mostly prose, and mostly non-fiction. More like a diary :)
I will tell you this though, writing words and thoughts on a page, whether it's sentences forming paragraphs or tasks forming a lists - is one of the most immediate forms of creative relief/creative expression you can engage in. You can write with a marker on the walmart flyer from the junk mail and feel better instantly! I encourage you to try it if it's new to you, or to commit to it more consistently if it's something you already enjoy. The written word can be a big part of your daily creative practice too.