People like to say that they are their own harshest critic, but that is not true for me. My girlfriend is far and away my harshest critic. She gives me the roughest feedback and is absolutely brutally honest. If there is something she doesn't like, she'll just rip it to shreds. It'll drive me mad. It'll make me so angry. But the moment she says it, I know she's right, and that makes me even angrier. After it's been stated it will seem so obvious, and I will feel so stupid.
It's always hard stuff to hear, but the book will be better for it.