I used to question as to why when a certain boss died, people would leave the group. It frustrated me for a long time. But, I think I am beginning to understand.
I have run LFR, normals, heroics on my warrior all in hopes of getting new weapons, maybe a new trinket. After 2 days full of dungeons and LFR, I find myself wanting to leave if I am only there for one thing and it hasnt dropped in ever.