If you own one, Keel himself suggests that the reason you may not have previously been able to keep a diary is perhaps because:
"1) Not every day is very eventful.
2) It actually takes a lot of discipline (regarding 1 even more so).
3) In retrospect, many find what they have written quite embarrassing."
All three of these things are problems I have encountered when keeping a diary
I happened to land upon the Simple Diary while browsing Amazon. Initially, I looked into Wreck This Journal after watching a YouTube video of what to do with it. Great, I thought, but definitely not for somebody who cringes at torn paper, paper with anything other than pen on it, paper with bent edges, etc etc. I followed a ton of recommendations and eventually ended up at the Simple Diary. Just the word 'simple' appeals to me greatly. Who doesn't like simplicity?
I instantly liked the concept. Keel has clearly thought out each aspect of the book, so much so that when you open it up, you have a card congratulating you on purchasing it and giving you an almost horoscope-like description of your personality. For example, I bought mine in lime green (I'll be honest, it was the cheapest one on Amazon at the time), suggesting "you are content despite your grand aspirations" and "you are a sincere person in many aspects". Of course, these statements are fairly vague, but from the moment you open the book you are encouraged to look deeply into yourself and who you really are, a theme that carries throughout.
In short, Keel's Simple Diary is (in my opinion, of course) a diary for lazy people. You fill in the date, choose an adjective or metaphor to describe your day, explain why in less than two lines and make a couple more choices over random factors in your life. What I find so great about this book is that by giving you seemingly random choices, it truly makes you stop and think hard about which of the three describes your day. Is my day a) crucial, b) open-minded, or c) immature? Well, I had something important happen today but I also had a stupid argument... Etc etc. Each day also comes with a quote. For example, the first day in mine says "If it's not there, there is nothing to find out."
So, overall, why do I like it? Well, I guess it's because there are a lot of things present that I personally find appealing - the positives far outweigh the negatives and for around £7 I think it's definitely worth it. I know I've spent £10+ on notebooks that never got used for diaries after all, so it's not like it's a waste of money. There's also a volume two if you find that you really love it but have run out of pages.
To sum up...
Great, new concept
Focus on thinking about your day properly
Fun factor present
Range of colours so not gender-specific
Great for people who want a record of their life, but not necessarily in-depth or that covers absolutely everything
Allows you to sum up your day and think about how things have balanced out
Probably great for people who have lots of thoughts and feelings but don't keep diaries because they struggle to actually turn their thoughts into sentences
Oh, and according to the back of the book, a portion of the proceeds are being donated to reforestation... that's always good
Elaboration on each day is limited
Could be argued that some day choices make no sense or would 'scare off' those who weren't necessarily hugely deep thinkers
If you have any questions, fire away in the comments below!