I don't think anything can prepare you for a crew to come in and actually film you as yourself. It's kind of frightening to think that all of a sudden people are going to know how you are, and how you act on a day-to-day basis. ↗
It's amazing that for actors mostly, it's a risk to attach yourself to a film that you don't know whether or not it's going to even be made and if you sign on, in doing so, who else is going to be in the movie with you. ↗
And yes, there's a simplicity to writing books because you're not a member of a team, so you make all the decisions yourself instead of deferring to a committee. ↗
I mean it's the most objective industry in the world. If your numbers stink, you're out. If your numbers are good, you get more money. It's the most Darwinian, it's beautiful, it's brutal, it works. ↗