Back when I first started playing WoW, I developed a lot of bad habits while leveling.
My first 45 levels or so, Quintalan was Holy Spec, but since I rarely went into instances at that time all I knew how to do was quest --and kill things-- using my weak Holy Spec capabilities. To compound the problem, I looked at gear the way I would in my pencil and paper RPGs: a little bit of Intellect and a little bit of Strength never hurt, and look --something with Agility! It never occurred to me that maybe I ought to concentrate on one stat and let the other gear fall by the wayside.
After I switched to Ret --at Soul's suggestion-- I developed another set of bad habits. For example, I'd use tanking abilities in my attacks, which really don't go over well when you get into an instance. And when leveling, I didn't have a concept of a rotation. Sure, you could argue that Ret Spec in Wrath didn't have a rotation --and I'd not disagree with you either-- but the basic understanding behind a rotation escaped me.
Oh yeah, I was a noob. I had my share of "HEY STOOPID!" moments out there in WoW.
It wasn't until I started pugging and got serious about understanding how a Ret Pally works that I finally broke out of these habits. I tinkered with key bindings and how much you could load onto one button until I realized I needed more granularity than that. (Such as saving Avenging Wrath for Bosses; you don't need it for trash. Therefore, don't try to bind it on any of my attacks but leave it on a separate button.)
Even when 4.0.1 dropped I didn't have moments quite like those first few months of playing WoW, and for that I can thank Tomakan. He was mired somewhere in the 40s when 4.0.1 was released, and so I had plenty of time to work out how the new Ret rotations ought to work without all the clutter of higher level Ret capabilities.
But now, after having spent time leveling in the Cata zones, I've kind of backslid a bit. I slack off on my rotations because I can, unless I'm dealing with multiple enemies at once (or an elite). I've got some nice new skills on both Neve and the Pallys, but I haven't really adjusted my key bindings.* I know that the Cata instances are harder than Wrath, but I haven't tested the limits of how quickly I can go through my rotation without pulling aggro.
WoW is still a learning process. Maybe if you work at it hours a day for most days of the week, yeah, you can top out at a high level. But most of us don't have that amount of spare time. To get competent at your class, you need to dedicate some time, but nowhere near the levels seen by the elite raiding guilds.
Unlike my noob experiences, I know what I need to do to get back on track. I need to get into more Cata instances.
Am I worried about getting into Cata pugs? Not really. I like to be prepared, and if I can't be prepared, at least be overpowered. What's killing me is the time factor. I don't have the time to set aside two hours to cover a pug right now. I can run BGs more quickly than what I've discovered via the Cata pugs I've been in, so I end up queuing for them instead. (When Alterac Valley is looking to be quicker than a Cata pug, you know you've got time issues.)
So for the time being, I'm going to continue to quest and accumulate a punch sheet of things I need to do. I'll get around to it. Someday. Maybe.
*I instead lust after a Naga Razr, thinking about adding buttons there rather than upset my current balance.