what was your favorite wow patch ever

Mine was probably the gates of ahn qiraj because even though i was a complete noob and wasn't anywhere near max level i enjoyed the sense of community you got from the event and it felt like a real war effort. Because of this i actually enjoyed farming wool cloth for the war effort because it felt like i was really making a difference. Everyone on the server was donating whatever they could to the war effort to achieve a single goal. It really made the server community come together. I wish blizzard would make an event like that again it could really help the current state of the community

What was your favorite patch in wow and why?