#7: Too Many Cooks Spoil the Soup
The flip-side of the Golden Word Syndrome is when a writer takes every advice as gospel. They'd change their manuscript as soon as someone, especially an agent, says something needs to be changed.
That shows us that the writer isn't confident with his or her own writing, is too eager to please, doesn't have a clear vision of the story and characters, and can't tell good advice from bad.
Remember this: suggestions and critique are only opinions. Opinions can change. Opinions can differ from one person to another. Opinions can be wrong, or at least not applicable. There's no right or wrong, only what makes sense.
While we writers must grow thicker skin and learn to accept criticism, we should also learn to sift through the barrage of opinions, consider them seriously, and pick and choose which ones make sense to us. Writing is a solitary act, and it's good to have outside input and feedback and support. But ultimately, we're the creator of that work, and we must hold true to our own vision. No good is going to come out of "writing by committee."
And remember this, just because someone else doesn't like what you write doesn't mean it is shit. It just means, well, someone doesn't like it. We all have different tastes. Instead, focus on what makes sense: if enough readers think your story is confusing, then chances are there is something wrong with the storytelling. If enough people correct your grammar, chances are you need to brush up on it. If enough readers tell you your story starts too late, chances are you probably do have a wrong beginning. "Chances are." There is no absolute, only "what makes sense." Do consider all the advice with equal faith, but faith shouldn't be blind and without reasons.
Most important, develop and improve on your skills and listen to your own voice. Practice, practice, practice. That's the only way to gain self-confidence.