When I first rolled my Priest I never dreamed that I'd end up being the type of person that bailed on their class when the going got tough. I guess, in retrospect, that is just what I've done.
I don't think I've been the person who consistently jumps on the current flavor of the month class/spec. When Holy/Holy was the spec to be I was the hybrid Disc Priest who took Divine Spirit so our raid could have the spirit buff. I tried out Holy/Holy towards the end of BC, but I never really could get the hang of AoE healing. During Wrath I was a Disc Priest all the while Pallies were the crowning glory of single target healers.
With Cataclysm, and the changes and more changes and more changes to Discipline and the way bubbles work, I just couldn't do that to myself. I just don't have the time or patience or ironically the discipline to cope with the bubble rollercoaster. I tried Holy again, but I still just didn't feel the AoE.
I've tried playing Shadow, but it just feels so gimpy when compared with a Mage or a Hunter or even a Warlock. It feels like Shadow Priests can't even compete in DPS anymore. I don't expect to top meters, but its disheartening to be so much lower on the meters than others.
The Priest class used to inspire me. I had such pride in my class. My oldest WoW friend and I agreed and pronounced loudly that Priests were the best class in the game. We could do amazing things, the two of us, him Shadow and me Discipline.
Now we are both leveling Paladins (and loving it).