Enjoy leveling: Once you hit 60, the game experience gets better for a short time, and exponentially transforms into a rep/gold/reagent/potion/instance farm-fest. Getting from 1-60 was my favorite part of the game. Everything was new, there were two massive continents to explore, new instances, new experiences... I loved it.
I hit 60, and all that changed. It was great at first... I started raiding, getting some good gear, but after running MC more times than I'd care to count, and doing BWL until I could do it in my sleep, I was burnt out. I was sick of having to spend my playing time gathering reagents and potions for these 6-hour borefests, and not to mention the gold I had to farm because of my class. As a warrior, my repair bill was ridiculous and kept me poor for the better part of a year.
I turned to some more PvP, and this just pissed me off even more. It was fun and all, but in order to get anywhere you had to PvP A LOT, and without a good group behind you, this was a horrible, arduous task. After getting 120k honor in one week and moving 3% (three ****ing percent) closer to rank 10, I called it quits on PvP because I couldn't take it anymore.
I found myself making alts, hoping that the long-lost feelings I had for the game would return, but I knew the entire game like the back of my hand and nothing was new. The game was pretty much dead for me, but I persisted and continued raiding and standing around in Ironforge doing nothing, because PuG's were horrible, and everyone in my guild had such good gear they couldn't be bothered to do anything but MC and BWL.
And so it came to and end, and I quit the game.
Now, after reading that small novel, please don't rush through leveling. It's the most fun you will have in this game, and you will make some amazing friends in doing so, just as I did.
Despite my obviously malicious feelings towards end-game, some of the most fun moments in my gaming history took place at level 60: The first time we dropped that ***** Onyxia, the first time we killed Ragnaros, the first time we killed Nefarian (that was ****ing awesome), the first time we killed the first boss in AQ40, and the other bosses we downed, all of those were the most fun moments in the game, but couldn't save the game for me. It just got too boring, and even the prospects of new loot couldn't keep me hooked, and so I retired my character.