Like many people have said, WoW will always hold a special place in my heart. I didn't start playing until Wrath came out, I resisted the urge to come to WoW for as long as I could because everyone told me how addicting it was. I started out with an Undead Warlock, and to me the world was so big, the immersion was deeper than any game I had ever played.
I remember playing through the 1-60 content, at the time not even realizing that the game was even broken down into expansions, sure I bought them, but once in the game I was just lost in the world itself. Around the time I hit level 60 I had heard about this quest to get my Dreadsteed, and I was mesmerized by it, then I found out I could just pay for it, but I was already immersed into this game so much where the only option to me was the quest, plus it was cheaper! Haha. I searched Orgrimmar and finally found another Warlock who had the items to summon the boss, got a small group together and went into Dire Maul, after what was the most amazing thing I had seen in the game to date, I had my Dreadsteed mount and I was the happiest Warlock this side of Tirisfal!
I eventually made it to level 80, and the same Warlock who helped me with my Dreadsteed quest invited me to her raiding guild. I had no idea what raiding was yet, but they showed me, helped me to gear up with crafted gear, running heroic dungeons, helping me play my class. I leveled Demonology, and at the time had no interest in playing anything else, the Felguard was my bro and there was no separating us. But alas, I was talked into switching to Destruction, and I hated it at first.
The more I played, the more I did these heroic dungeons, and then got into the expansive raids, the Lich King taunting me all the way, I was excited, I had never been so excited in my life to put that guy down when the time came. I took everything my friends taught me and I applied it, and I became a pretty good Warlock, earning myself some top spots in raiding, always competing with the 4-5 other Warlocks in our guild, it was healthy competition, we all stuck together, there was no elitism. I FELT like a Warlock, like we were this dark cult inside our guild who relied on each other for more and more power.
And that brings me to my number one reason why I don't play anymore.
It's just not there anymore. The story-telling isn't bad, but it's not like it used to be. Maybe it's nostalgia, but I just didn't feel like Cataclysm, or even MoP delivered their story half as well as Wrath delivered the Lich King story. I felt like a Warlock, I felt like this guy was coming after me, testing me, and that I was growing in power as the expansion went on. I felt like I was part of the story. The world felt so alive, especially when you could see the Lich King's reach in multiple dungeons that you ran almost dailiy.
In the beginning of Wrath you didn't see nearly every dungeon on a daily basis, you still had to put groups together and then fly to the entrance. I didn't care though, I loved my magic carpet from tailoring! People would tell me about attunements from Classic and BC, and it made me want to do them, and I was lucky enough to get to do a lot of them before they were removed. Granted I was 80, but it was fun seeing the story from expansion past, getting to be as much apart of it as a I could at that point. Learning how to solo lower level raids and whatnot as a Warlock was a very welcome challenge.
LFG came and provided a huge convenience, even I loved at it first, but then I realized, LFG is what as killing the immersion for me. Of course at the time, it wasn't too bad, my server wasn't large, and I had gotten to know a lot of people on it, and a lot of times finding a group or half a group in trade chat, and then queuing helped alleviate that.
I ended up shelving my Warlock for a Death Knight during ICC because my guild's OT went AWOL. Learning to tank was fun, and I enjoyed Death Knight tanking specifically, but through Cata and MoP the game just lost it's appeal to me. It suddenly became more about loot and min/maxing for me, and less about feeling like I was a part of this huge world and enacting meaningful changes through raiding to this world.