Actually this is exactly me. I used to focus on normal (tiny bit of heroic) raiding while it was current content. I thought I was having fun, but taking some time away from that - I found that it was actually somewhat stressful progressing and even though I still felt a little goodness from finally downing a boss after two weeks of wipefests on that boss, it was all just getting old. Seeing the same people fail at the same mechanics...
LFR is just completely stress-free. Sure you can run into bad groups, bad players - but I just approach all this like a good comedy movie. I don't take raiding seriously anymore and I love that. And I know I am not alone with this change.