What do you mean, my writing isn't perfect? I like it just the way it is! That is...until I rewrite it and see how much better it is!
In my day job, I write reports, memos, and presentations for my company's executives and board of directors. It's a high-profile job, and everything I send out must be perfect. Pressure? Sure, but honestly it's not too hard to be successful, thanks to my feedback process.
No one can write the perfect anything the first time, and no matter how good we are at editing our own work, there is nothing like having a second, fresh pair of eyes look at your work. They may see a mistake you didn't catch, or they may point out a plot hole you'd missed, or they might find places where you just need more detail. In any case, having someone edit your work is usually highly helpful and rarely a waste of time...depending on your attitude.
At my job, we say, "Red is the color of love!" If someone hands me a report that I wrote with red pen all over it, it's because they love me enough to put time and effort into finding ways to make it better. The longer I'm in the job (almost two years now), the less red pen I see, because I've learned so much about writing these types of things.
The same goes for my fiction and articles. My sense of self preservation wants to launch a campaign to fend off attack every time someone reads my work and offers criticism. After all, I wrote it just the way I'd pictured it. However, after I follow the very excellent advice I've been given and rewrite or revise the piece, I'm always happier in the end.
I've come across many people who were very defensive when they asked for feedback on their writing and didn't like what they got. They argued, they tried to explain what they were trying to accomplish with the piece, they accused the critic of being jealous or just plain mean. What is the point of this? What did you learn? If you have to explain what you were trying to accomplish, you didn't accomplish it.
Keep in mind that your critics are just offering their opinion...but it's the opinion of a reader. Readers are your audience! If you're writing for yourself just because you like to, that's fine, but don't put it out there and expect everyone to like it...and certainly don't ask for critiques. Of course, many people who read your work will disagree with each other about what they do or don't like. You'll have to pick and choose which feedback to use, and how to use it in such a way as to preserve your vision and voice. When you get defensive and refuse to consider feedback you're given, you're not only missing an opportunity...you've wasted your critic's time.
PS...thank you to Michelle L Devon, editor extraordinaire!