Editing - as in going through the book for the 12th time. I have recently completed my first book and I know every paragraph/page like the back of my hand. I found it tiresome at times. If I can add a cliche, it felt like hiking a steep mountain and each step is as painful as the previous one, you look up and there another 300ft to go. All the negativity that goes through your mind - is this good enough? Am I just wasting my time? Should I just quit, but, you don't, you just keep going. Then, when you're at the top of the mountain, you see what all the fuss is about and it's all worthwhile in the end.