Receiving feedback is a vital but uncomfortable part of the writing process. It can also be mighty confusing. Someone asks why you've hardly described the hero's looks, while someone else enjoys being left to imagine him. One person raves about your gift for description, while another turns their nose up at your purple prose. Someone adores the hilarious way your ditzy heroine keeps tripping over cake trolleys – but someone else cringes at her vacuousness, making you panic and scribble in a paragraph about her love of Renaissance literature.
When it's informal feedback – from friends, an online forum or a face-to-face writers' group – there might also be issues with the individual commenter's perspective. Is it a family member who just knows everything you do will be brilliant? Is it a kind person who wants to help but worries about hurting your feelings? Is it someone employing Machiavellian tactics to climb the chart on a competitive writing website? Is it an arrogant or insecure writer who feeds their ego by belittling others? Then there are those who have interesting views on your work but can't express them – they might say 'It was great!' or 'This bit doesn't read very well,' but that's the extent of their analysis.
What you want are sensible, polite, honest and thoughtful responders who can explain the reasons behind their views. But even they can end up being unhelpful. They know you want detailed comments and that you won't fall for being told you're the next Milton, so they will find something – anything – to show they are taking the task seriously. They might point out a 'mistake' – but if the same thing were in a published book, they'd see it as a clever literary device. People trust a published author to have a good reason for doing something, but they don't necessarily trust you in the same way.
For all these reasons, I'm wary about rushing in to make changes on the strength of one person's opinion. After a few days, once the sting of criticism or the joy of praise has worn off, maybe it will turn out that the person was right. Maybe a few people have made the same comment, or maybe I knew deep down that part of the story didn't work but I just kind of hoped no one would notice. Maybe they have raised an issue that never would have occurred to me otherwise, and that makes sense of everything. But it's also possible they have their own agenda or that they've completely got the wrong end of the stick.
It's great to have trusted readers who can enlighten you about how to improve your work – but if you've carefully considered feedback in cold blood and concluded that you don't agree, I think it's equally important to trust yourself.