Have just finished reading ‘Spare’.
These are just a few of my personal observations.
1) Harry has never got over the tragic death of his mother. Should have had more counselling back then, assuming he didn’t, but 25 years ago, thoughts on such matters were different.
2). William, being the firstborn and second in line to the throne, was always going to be treated differently to Harry. He is also much more academic, and this has rankled with Harry.
3) I didn’t find the lengthy sections about his army life the most interesting part, but think that army life suited him and he seemed good at it.
4) It’s very clear, Harry makes no secret of the fact that in his 20’s, he is desperate to meet someone, get married, have a family. This doesn’t happen with either Chelsy or Cressida.
5) He cannot believe his luck when he gets introduced to a certain Meghan Markle. Besotted is an understatement, and to think she knows nothing about the Royal Family? 
Poor, deluded Harry. Meghan had her eye on him from the get go- a wealthy prince of the realm, but troubled and needy, just ripe for the picking.
She could have helped him so much more, I feel. Instead, she has fed on his insecurities, coming across as a mother substitute in many ways, and not helping him move on from the past.
6) The last section of the book is, of course, the downward spiral. I think there are issues from all sides, but we only read Harry’s side of it.
I’m glad I‘ve read the book, but it wasn’t comfortable reading.