@Tom: I'm assuming you're talking about WoW, because that's the only MMO I've ever played with that problem. In WoW's case, the problem is actually there ONLY because of the solo-push that Jason was talking about. Nobody wants to group, because you don't have to, so that nobody bothers grouping, so when you do want to group you can't, because nobody wants to group because nobody has to. The solution to puttering around in LFG for hours is to make a game where you have to group for much of the content. Of course everybody disagrees because they've only ever played a game where grouping is hard as hell because of the above reasons.

So now we've got a standard-setting MMO that's made it difficult and unreasonable to group with people, so that when people think "grouping," they immediately groan and opt for solo content. The other standard-setter (Guild Wars), has made it again unreasonable to need to group with people. This is not the way it should be, and its not the way it was, and its certainly my biggest gripe with MMOs.

I want to play an MMO because of the people in-game; not because I want to play a game beside thousands of others, but because I want to play a game WITH thousands of others.