Played MoP for a bit and then quit for good, never going back. Tried one of the "free" WoW servers or whatever...played for a bit and realized it's just not me anymore. The thing that made WoW amazing was playing vanilla/TBC/WoTLK and feeling like you were growing alongside other people. Doing quests with friends, being invited to your first guild, having people whisper you the second you logged on to help with dungeons or quests, learning about raids and focusing on that, staying up late at night just mining ore so you could talk to friends. The userbase was completely changed by Cataclysm. So many areas of the game are just dead. Nobody leveling since you can buy that shyt.
LFG and LFR felt like the end because it kinda killed the server identity. I remember when I knew who the top 5 tanks on my server were (including myself), who the top healers were, top DPS, best raid leaders, etc. Doing dailies late at night felt like a fukking all star game when you were elite and had elite friends...you could finish that shyt in like 8 minutes, and then say ayo lets do another quick dungeon. Before you know it it's 1AM and you just having a blast. Homies sign out, but maybe a couple stay on and you just start doing your profession and chatting. Someone hops on their alt and is getting ganked by horde so you head over there to help. Or your warehouse homey gets off work and gets home at 2AM and you do a quick dungeon with him before going to bed.
College years. Go to class, get home and play WoW, go out to party, come home and play WoW. Back to school the next morning.