I've been playing WoW since Vanilla, and I missed out on raiding old school. I did get a shot at a few pugs for AQ40 and was laughed at frequently for still using the Hypnotic Blade, lol. I know it wasn't the best weapon or even close to it for a mage, but I used it because I had fun and didn't care what my gear was like.
Of course times have changed and I started raiding heavily in BC and took down Illidan pre-nerf, and I started loosing interest in anything but raiding. Then Wrath came out and I leveled my character fast, missing out on a lot of the background lore and quest lines just so I could start raiding Naxx. I did this with four other toons and continued this style well into Ulduar.
Finally life intervened and I had to stop raiding, and I realized that I didn't know how to have fun any more. I barely play anymore, accept to play the auctions. I do not know what it is to not be a raider anymore and just have fun.
So that it what I look forward to in Cataclysm, re-learning how to have fun again in a new world.