Writing a Dissertation; or, Why It's a "Process"

Process Example #1:
Because I'm revising the third of my three chapters that deal with my texts, and I've just decided that one of the plays I was going to use is getting thrown out. In its place are two different plays by the same playwright. It turns out, they will be a thousand times more helpful. I could not have known this when writing my proposal. I could have known before drafting the chapter only if I'd read every word of all the secondary sources that deal with this playwright, or if I'd sat down and read each of her 16 plays. Instead, I wrote. I put something on paper, and I got some feedback from my advisor. Now, I've returned to the chapter with some big changes, but the most important thing is I know *why* the changes are important and necessary. No, scratch that, the most important thing is that my chapter will be better than it was. Longer, but better.

Process Example #3:
I think I'm going to cut an entire "set-up" chapter. I don't think I need it, and I don't think it fits within the scope of the dissertation. In order to talk about Thing X in women's comedies between 1685-1722, I had previously planned to mention how Thing X existed in women's writing before 1685. But now, I will not. I hope my advisor agrees with this decision. If she does, that will mean Very Good Things for my timeline and for the (as of yet shaky) confidence in my ability to know How to Write a Dissertation. Because really, sometimes I just don't believe I can/will do this. Does this make me intellectually needy?