There is a certain sense of achomplishment that goes with finally completing a book. When it is all finished, the writing, the editing (Ugh), the blub, and the acknowledgement, it's over. Now all you have to do is sell it!
And that my friends is the kicker. Just getting it published is only the start. Whether you self publish, or the biggest house in the country takes you on you still have to work at selling your work.
Even with a great book like "ICE" you have to sell. You use your "Ole Boy Network" you lean on friends and relatives and finally....
You sit down in front of the computer and start on the next one. It proves you are crazy and a writer.