I love feedback on my writing, like, to a near masochistic degree, so I'm all about writing groups, crit groups, CP's, beta-readers, all that good stuff. Call it what you want, if you can get an objective eye to look over your writing and honestly tell you what they thought (good or bad), that's an awesome thing.
But I'm also pretty quick to warn others that finding good people can be difficult, so be smart and be selective.
Janice Hardy (if you're not following her blog yet, you really should) did a great guest post today on some of the problems you can run into. No, this article isn't fanning the flame of negativity, she's really giving a lot of things to watch for so you can possibly know how to avoid/handle them if you ever get into that situation.
I've personally seen all these, both in real-life meetings, and in online relationships.
...and I know when I started getting my writing critiqued, my personal 'worst' was telling others, not necessarily that they were wrong, but I would try to point out why something was the way it was.* This could have been handled differently (and I think I'm better now), but I think each of the problems are also things that change as the writers grow together as long as there is trust and honesty between them.
I'm really big on asking questions. If someone finds a problem, and I don't really understand why it's a problem or how I can fix it, I ask. Sometimes it does feel like I'm asking a stupid question when it's clearly obvious to the other person what the problem/solution is, but I don't see a reason to feel embarrassed about doing that because I genuinely want to improve my writing. Feeling silly in that moment is a lot better than going away not understanding what the problem is... 'cause then you'll never fix it.
...and if I've learned anything about writers, we love to talk about writing as much (if not more) than we like to actually read/write, so someone asking us to explain further our opinion of something, well, you might as well just wrap that up in a bow, 'cause it's so much fun to analyze characters/plots/etc.
We are all monkeys madly typing away on our keyboards, hoping our next line is Shakespeare instead of nonsense, but it might not be us, it might be the monkey sitting right beside us. We're not in competition with one another, we're a group who are like-minded, goal-oriented, and perhaps just a little crazy, so I think it's great to help each other out and genuinely be happy for the monkeys who succeed one step before us. Between our own nonsense and their lines of Shakespeare, we can each improve and grow.
*this is primarily because I'm prone to over-thinking, even down to the exact words used within a sentence and what double meanings they could possibly have.