As much as I enjoy writing, it is much more fun when the words are pouring out of your head than when you are culling 10 pages down to 5. It is also painful to discard all your ideas in a scene or chapter and start over. Awareness of that kind of erroneous fixed-pie thinking, the idea that there are a finite number of words available for consumption, doesn’t make it feel better.
And finally, the realization that you’ve only been writing your novel for two weeks and have already trashed 70% of the production is a bit of an ego blow.
<sigh>
Gotta keep going!