Okay, just a bit of a disclaimer and a warning. This whole thing is a half-rant/half-suggestion based on some observations in the former SW MOC forum and the LEGO forum at the old FBTB. It's not directed any anyone in particular or any groups. It's not a call-out or anything like that. Really, it's just a move to try and improve what could very well be the most important part of our forums. And sadly, right now, it's probably the most underused.
First, let's talk about what the best thing is about LEGO: you can build anything you want. That's what makes it such a wonderful hobby and toy. It's pretty much the only response that needs to be written for every "I Wish LEGO would make such-and-such" thread. Have bricks, can build. Sure, we all have varying degrees of building skill and brick selection, but if you can wish to buy a new set, you can wish to buy some bricks off Bricklink. Probably cheaper that way too.

The reality of the Internet is that you're putting yourself out there with every post. If you're a passive member, you're only here to read, you're not posting anyway, so it's a non-issue. But when you do post something, be it a creation or an opinion, you should expect to be held up for criticism. Such a cycle is necessary for a healthy community to continue and grow. It makes everyone better by continually pushing for a newer and higher standard.
In the scope of LEGO, it makes us better builders. Sure, it's nice to hear comments like "wow, that's great" or "I love it," those don't improve my skills. Fifteen responses that are one line long do not help improve my model, or bring up a technique that I'd never thought of. Honestly, that's the kind of responses I could do without. Yes, I appreciate a few of them, but I'd much rather have one response of "you should try out this block here, and add a bit of shape to this. Maybe something like this..." than 100 telling me I built the best thing since the Slave Leia Dancing Band.
This isn't to say that I'm advocating free reign in talking about how terrible something looks. It's about the art of "constructive criticism." This means adding to the discussion along with advice or a solution, not just tearing apart (or complimenting) something.
That's the whole purpose of a MOC forum, to get feedback. If you want to just post pictures of your build, try out Flickr or Brickshelf. People can look, oooh, and ah all they want. This isn't the place to come and get that.
The cornerstone of constructive criticism is that you critique the subject, but also give advice on ways to improve it. Members who provide feedback like this are not elitist, they're trying to help you become a better builder. And it can vary from person to person.
On the same note as comments like "I love it" or

The moral of the story is that by posting in a MOC forum, you're expecting and accepting feedback and constructive criticism of your work. Don't get worked up if someone isn't wowed by your model... it happens to all of us, and there's always room to improve a build.