I think this is a good book but not the book for me. 
This may be a hard read for those struggling with depression and suicidal thoughts but it does help encourage your brain to look deeper. I think it’s nice the way the author showed negative events and emotions change given the perspective of what’s actually happening. 
That being said, I found this a bit slow and boring. Halfway through the book, I felt like giving up cause what I was reading wasn’t pulling me in like the first chapter. The character lives through different choices of her life like an alternate or parallel universe. After the first two, I felt like my eyes were unfocusing and my mind wanted to skim through the repetition. I didn’t find the character lovable(possibly due to the British background) but she is relatable. I may have enjoyed this book more when I was in my self-hating youth era. 
It is only a 288 page book and has easy to read language. I do appreciate the analogies with chess and green books (grass is always greener on the other side). There are some good literary device use here. I don’t regret reading it as it reminded me of the annoying pessimistic person I used to be. It won’t be on my re-read list, but it may be on yours!