On writing a synopsis

Am I the only writer who enjoys writing a synopsis? I have always found it helps my creativity, keeps me motivated and focussed . It's how all of my books begin.
I'll tell you how I began writing them. When I was writing situation comedy for radio, and television I learned a lot. I listened to and I watched other comedies, and I read books about writing for both radio and television. When you have to tell your story in 27 minutes or less, then you can't waste a moment, and have to have a plan before you begin. A synopsis in fact.  You work on the story first. Then divide it into scenes. Each scene should move the story along and end on a mini cliffhanger so the listener/viewer will want to stay switched on to find out what happens next. Hook them with a great beginning, and build to the funniest climax/line you can come up with.
    So when I was writing my first children's book, Run Zan Run, I simply used the same principle.
  You think that sounds too formualaic?
  Well, do you think  the Pope  gave Michael Angelo  a set of step ladders and a pot of paint and said.  'Away up there and paint something, son.'  And then Michael Angelo goes up with his brush, finishes his painting and realises there's no room for one of the legs? No. He made a plan. He knew the exact size of the area he had to work in. He knew exactly where he had to begin, and how to fit everything in. He made a plan. and he created a masterpiece.
   He wasn't the only one. Da Vinci began with a mathematical plan for his masterpieces, so he could get everything in proportion.
   And if it was good enough for them, it's good enough for me.
   Not that I'm writing masterpieces! But I do want my books to be the best they can be.
   So I write my synopsis, and as the great Roald Dahl said,' once you have something written you have something to change.' So as you can imagine, it does change a lot.
  
   I think of my book is like a journey, and for a journey I need a map.My synopsis is the map  I know exactly where I am going to start from, and where I would like to finish. Say, London.
  But on the way, I may take some interesting detours. I may be held up by roadworks, there may be diversions that set me on a different path. I could meet interesting people I didn't expect. But my map keeps me heading in the right direction, and eventually after this, hopefully, exciting, surprising journey Iwill still end up in London.And Wow! the riots are going on. Something I didn't expect when I started off.
  The synopsis keeps me focussed.
  So here in a few words, is how this works for me. Won't work for everybody of course, but this is my way.
 I write a mini version of my story. My synopsis.Then I divide it into chapters, each chapter must move the story along. Each chapter should end on a cliffhanger. I hook them hopefully with that first chapter, and build my story up to a thrilling climax. Giving readers the ending they want, but not in the way they expect it.
  Then I start writing, and the adventure begins.