Criticism . . .

 . . . is your friend.  Repeat after me.  Criticism is your friend.  I'm talking those constructive notes from CPs, judges, editors, agents . . .  Most of them, even ones that might seem harsh (or are harsh) have something of value.  The ones who slam you, offer nothing constructive or useful and seem to be taking their crappy day out on you -- those can go in the trash.  Those only make you second guess yourself.  Anyway, the notes you receive could be something you already know, deep down, needs to be addressed.  It could be something you haven't thought of.  And it could totally go against everything you believe in where your book is concerned.  So what do you do when this happens?

Easy.

You listen.  To every single thing.  Even if, at first, it totally doesn't 'ring' with you.  Here's my rule of thumb -- if anything at all (even something as small as one word) pulls a reader out of my story to write a note, it's potentially something that could pull another reader out of my story.  So give every comment and note serious consideration.  Try to figure out why that particular thing stuck out.  

Often times, I'll get notes that are spot on and sometimes I know immediately a note doesn't jive with the story I want to tell.  It could even make me bristle at first, but I have to take a moment and remember my rule -- there is a reason that particular thing caused the reader to stop reading, and I don't want another reader being pulled out of the story in the future.  In the end, I might not address the note the way the reader saw it, but I do give it time and thought, and usually I'll end up putting my own spin on things and amend the story in someway.  And there are times when I don't, but that is only after I give it a lot of consideration, look at things from all angles, and talk to the person who gave the note (most often great things come from discussions like this).