I am, above all else, a healer. That's what I decided to be when I first rolled my paladin who has since seen and done amazing things across Azeroth. During BC, paladins were sort of a running joke (much like during Vanilla), but I stuck with it. I healed my metal-covered ass off. During Wrath, Paladins were shown tons of love.
Now, I know there are people out there who believed that Retribution Paladins were facerollers to the nth degree, and to a point, they were correct. By facerolling, you could pull off acceptable DPS. I say acceptable because it was enough to get through the dungeons and a few raids. However, the well-played retadin could produce numbers that would show a very clear difference over the facerollers.
Protection Paladins were much the same. Sure, the various buffs Blizzard threw at us allowed us to hold aggro reasonably well, with little actual thought required. However, the facerolling tanks would be known very quickly once an encounter didn't go textbook-perfect. The skilled prots would have no problems using the whole spellbook to maintain absolute control (and I do mean draconian levels of control).
Then, there were the Holy Paladins.
*insert choirs of seraphim and glorious parades in our honor*
We were gods. Plain and simple. A well-glyphed and well-played Holy Paladin could single-heal most current content. Tank and raid heals went hand in hand with Beacon of Light (back when it was 1-for-1 heal copying). Glyph of Holy Light caused all Holy Lights cast to splash to other melee targets in the area for 10% of the initial heal per target. We were unstoppable. PvP was very similar. Holy Paladins could dominate the battlegrounds, and if they were protected by one or two dps, the battle would rage for eternity.
I picked up tanking in addition to healing solely to learn the process and help my guild's tanks improve upon their own abilities. Through clever use of macros, I was able to reduce the standard 96969 rotation down to two keypresses, opening up the rest of the main action bar to more utilities and oh-shit buttons.
Regarding Holy Healing, I had a real problem with the Flash of Light crowd. Stacking Spellpower and spamming FoL was, in my mind, an abomination. It was an affront to the true nature of what a holy paladin was. Sure, it was one viable spec among many for one specific encounter, but the folks who took it to every single bloody fight afterwards made me want to tear my luxurious belfy hair out. But I was calm. On my server, at least, people learned that, if you wind up in a PuG with Hyperious, don't mention flash-spamming. EVER. He will calmly inform you that you're a blithering idiot, and then proceed to do triple the effective healing (not including overheals) on every fight.
I explain the godliness of paladins in such detail for this reason: We got so fat and lazy during Wrath. Mana wasn't an issue. Ever. Healing effectiveness wasn't an issue. Ever. Nope, we could kick back, throw down some epic heals, and practically drown in the glories that were showered upon us by our loving fans, the Blizz Developers.
Fast forward to Cataclysm. Hyperious sat quietly in Orgrimmar. He didn't do the dungeons. He didn't do the raiding. Not as a healer, not as a tank.
Why, Hyperious? Why not continue your reign of glory?
Deathwing broke the world, then broke everything I ever knew about being a paladin. Holy Power threw me a curve. I couldn't adapt. Not yet, at least. I went from completely ignoring my single resource as both a healer and a tank to having to actively focus on two resources. I couldn't quite come to terms with the idea. But after much questing as a tank and levelling and so forth, I finally felt confident enough to run a few dungeons. As a tank.
Hyperious had forsaken his healing roots.
*insert depressing organ music and lots of flickering candles*
But this past weekend, I decided something. Damn it all, Hyperious, you're a healer! NOW HEAL SOMETHING! So I went to my bank and I picked out all the healing gear that I'd gathered during my quests. I hopped from alt to alt, gathering the required materials to get myself a few epic pieces. I gathered my strength (or intellect, as it were) and set off to do some dungeons.
I had to learn very quickly how healing works in this expansion. Gone were the days off eternally full health bars. Gone were the days of healing whatever I felt like and having the whole group benefit.
Triage. I had to learn not to heal. That hunter that caught a mechanic to the face? He'll have to wait. Sorry, hunter, but there's a tank in front of me and I can't spare the mana.
That was the hardest thing for me to overcome, the idea that I had to allow someone to sit at half-health for upwards of 20 seconds. This was nigh unfathomable to me. But I learned. I also had to relearn how to use my various cooldowns again. Divine Plea was now almost always on cooldown, and during the 12 seconds when it was active, I refused to heal. The high mana cost combined with the low effective heals made Divine Plea a very dangerous spell to use poorly.
The point I'm trying to make here is that Blizzard made me a god for a long time. I spent the time before that being something of a joke, despite my best efforts, and when godliness came about, I embraced it and enjoyed it. But I forgot my roots. I forgot what it was to have to watch my mana bar. I forgot what it was to decide which member of the group was in greater need for the heal that I could offer in that moment. And I forgot what it was to have to choose which spell I could afford compared to which spell was most needed. Blizzard spoiled me during Wrath, and the result was that I was completely unprepared for what I would have to do in Cataclysm.
My warrior, however, was almost completely unscathed during the transition, and I had no problem continuing his tanky ways through the dungeon grinds.