In case anyone is interested, I put up a couple of quotes on the
Notable quotes thread, here. The common theme spanning a career of writing was something that stood out for me on my recent revisiting of the Discworld.
The fact that the early quote come from a "disc-world" rather than the familiar "Discworld" highlights how Pratchett would sometimes keep working at ideas. You can see more examples of this in some of the pieces from his short story collection
A Blink of the Screen.