I was asking myself the same question when I saw people doing only LFR, but then I realized they play the game for fun.
Some people enjoy being LFR kings, some want to progress as much as possible, some are doing RP. I even know some people who are not really focusing on WoW as much as other games, though they're still playign it, it's just a game after all - it's made to be enjoyed.
Some people enjoy it because they do battle-pets, some people enjoy doing dungeon with friend and have a good laugh. That's all...
But if you're asking about whinning people - then I have no idea. I require from the game as much as I put in it. If I have coordinated group, Sim my character, prioritize Raid times etc. -> then I want to have good items, good DPS, nice mounts etc.
If I'm not really putting any effort in it then I shouldn't expect as much. But people usually want more and more at lesser cost.