Serial killer vibes aside, I always enjoyed the organized, methodical personality of the fictional Dexter Morgan. Even the opening theme reflects his highly ritualized (screech) and productive lifestyle.
Some people keep bullet journals just for tracking, without a daily log or a diary. The appeal is understandable. It’s an easy way to get organized.
The concept of a diary, journal or log is old as writing itself. As a plot device, it’s a way to keep a story moving forward, while giving the audience a view into the protagonist’s inner world. As a Buffy fan, I’ve found the role of diaries on the show intriguing. From the beginning, both Giles (the mentor) and Buffy (the hero) keep diaries.