Instances have been a big part of WoW and many other games. But instanced dungeons/raids are what make WoW unique.
From Deadmines to Naxxramas every instance is special in its own way. What is the best instance that you've done. Maybe you got many epics or maybe it was just pure fun?
Personally my best instance was deadmines when I first started WoW. Everything about WoW amazed me. I hadn't played a game like this before and when I first done deadmines I was probably as excited as...