http://www.gamefront.com/mass-effect-3-ending-hatred-5-reasons-the-fans-are-right/

That about sums up my thoughts on the matter.

Originally posted by Paradigm68

I been playing Bioware games a looooooong time (haven't played ME3 yet) and I think the problem might be the disconnect between the hype of Bioware's famous 'choices' and the reality that there isn't much real choice.  Clearly given all the build up and potential options from 3 games worth of minutia and impact they'd led people to think they'd have, there was no way they were going to be able to provide the number of ending to satisfy many people. So they opted for displeasing everyone the same way.

I don't think that's it, at least not entirely. There was a fundamental disconnect with the ending. I finished the game about 4 days ago, and I've since read countless essays and watched about a dozen fan reactions filmed as the closing credits were rolling, and I've noticed the same pall hanging over just about everyone that I saw in myself. The game underwent a radical narrative shift right at the end that had the effect of heightening emotions to a fever pitch and then utterly failing to provide any catharsis. As a result, people were just left holding this frustration without any place to put it.

***Major Spoilers*** involved in all of these:

One of the more interesting essays on why the ending caused such a disconnect: http://www.themetagames.com/2012/03/why-you-enjoy-art-and-one-problem-with.html (The grammar and writing aren't the best, but the author makes a fairly convincing argument).

Some YouTube videos that demonstrate the "pall" I was referring to:

http://www.youtube.com/watch?v=2NYjatgfMos&feature=g-like&context=G2390c58ALT2WEQwACAA

http://www.youtube.com/watch?v=8yvCugEpZ-Q&feature=g-like&context=G2d972bdALT2WEQwABAA

http://www.youtube.com/watch?v=LJAWHAd0lKo&feature=g-like&context=G2ff43a8ALT2WEQwAAAA

When you cause reactions like that in your fans, you've definitely done something terribly wrong. Those aren't the sullen faces of Twilight teens upset about Jacob or Edward, those are dedicated gamers who look like they're suffering from shellshock because the game drove them up to an emotional peak and then just left them standing there. I'm sure you're right, Paradigm68, the ending was almost certainly intended to be open to interpretation so that players could "fill it in for themselves," but it really did fail pretty spectacularly in that regard.

I realize the core user base of this site is more likely to call those guys "emo" than it is to identify with them, but I think that's doing them a disservice. The one quality I'd ascribe to all of them is "sincere." Those are guys who play Gears of War, and they're so upset they can barely make eye contact with the camera. Their frustration and disappointment is palpable, and it's exactly the same thing I felt. It's also why the BioWare Social Network's poll looks like this: