There have been times when I've been asked to do things and I've thought, 'This is great! This is a great script. But, I do not believe myself in this role.' I pretend I'm the producer and I think, 'If I was making this movie, would I cast myself in this part,' and if that doesn't feel right to me,
For the future, I would suggest avoiding subjects of too vast a scale. It would be useful to make out a list of fundamental questions on the matter to be dealt with, and discuss only those.
Good writers are in the business of leaving signposts saying, Tour my world, see and feel it through my eyes; I am your guide.