The problem with surprise

I do not know what I am going to say until it is said. (Murray)

1. Sometimes you DO know what you are going to say before it is said. This happens all the time.

2. There is a waiting for godot feel to sitting and waiting for students to find something to say. Sometimes they don't find anything to say (to which Don would say, that's okay, keep trying). Must we always discover what we are going to say as we write?