Master storyteller Ken Burns gives us his thoughts.
Ken explains great stories are about 1+1=3. I remember hearing years ago from Edward de Bono about great jokes taking you down an obvious path only to give you a realisation of something unexpected. What Ken is saying here is the same. A story has to have a surprising element to it much like humour.
No memory is perfect. In telling a story as accurately as possible it’s still possible to put emphasis onto the things within that make a truly great story. It’s the point of the story which will catch the attention and that point will catch the most if it’s a surprise revelation.