All sorts of problems present themselves to us authors over the course of a book. Research, knowing the craft, time management, and getting from page one to the very end--at least three times before it's worthy of sharing with anyone else.
For me, the hardest part seems to be the editing. No, I'm not talking about that first polish--I actually enjoy that step. I love taking my raw and rough story and playing with the word choices, the character's inner thoughts, inserting humor or angst where necessary and really just breathing life into the characters and plot. I'm talking about reading it three, maybe four times in a row looking for typos and/or grammar issues. That's the part where I get bleary eyed ;) I think this is why I strive so very hard to perfect as much as humanly possible on that first draft following the rough draft. I know that my last books have taken less time for my editor and I to get through than the earlier books--which is a blessing becuase by the time the book is ready to go to print, I'm almost sick of it.
Of course, there are those moments that I look forward to reading again (no matter how many times I've gone through them before) so that takes the sting out just a little.
For you non-writers who read my blog, imagine it this way:
You find you're favorite restaurant. You love one particular dish on the meal. You dine there once a week to begin with. Then, by the end of the first month, you're forced to eat that fabulous meal--for every single meal for an entire week.
Even though it's your favorite dish, by the end of that week, you might be ready to switch it up some and try a few other meals in there. It doesn't mean you don't like your "most favoritist meal" ever--it just means you need variety.
That's what happens to me. By the time the editing is done and over with, I'm sooooo ready to move on to the next project and start devoting all my time to that book.
Right now, since the Knight Inc. series has been completed, I'm preparing to write my YA series "Extreme Hauntings: The Kaylee Adventure Series" (working title) and dust off my infamous werewolf novel and see if I can't garner some more attention for it after I'm done with the rewrite.
Let me know what you find particularly difficult about writing, or what gripes you about reading :)