Three writers on the value of criticism.
Alex Ryder: Take criticism to be a positive thing and review your work accordingly. They may just have a point, or they may not. Be objective and then you can decide.
Margaret Callow: When others read your book, there is often conflict when it comes to a possible weakness. It can mean you end up altering something on one piece of advice and then having to change it again later. Now, I wait before making changes and then, if several people point out the same thing, I seriously consider and probably end up agreeing they could be right. If so, I make the change.
Dixon Rice (your genial blog host): I relentlessly search for criticism, because I don't recognize my own faults. Everything I write is golden. Then a member of my critique group asks if action ABC is consistent with how character XYZ acted in previous chapters...
Damn. Why didn't I see that? Thank you, guys.
Like Margaret, if just one person makes a comment, I may take it with a grain of salt. If a couple readers have the same criticism, it definitely must be taken seriously. That doesn't mean I'll make a change but I will certainly consider it. Sometimes the greatest value of a critique is forcing you to look at your work with fresh eyes and review the decisions that led to the incident in question. Then, if you decide to stick with it, you can do so with confidence.