I also logged into my priest alt again and played her for a bit, though not for long. Unlike my pally, this character's "original version" was levelled with a group of friends, and trying to recreate that experience alone feels like a very pale shadow of the past.
Still, it does trigger some interesting memories. Like learning how to use Power Word: Shield. I remember that when I first got it, I used to basically just attack the mobs and then shield myself once they got into melee and started hitting me. Then one day, I observed another priest soloing out in the wilderness, and for some reason she was shielding herself before even pulling. At first that made me scratch my head. Power Word: Shield has a thirty second duration, so if you cast it before combat you're effectively wasting a fair bit of potential shielding time!
Weakened Soul debuff, which won't allow you to be re-shielded for fifteen seconds after the first shield was cast. By pre-shielding, you could give Weakened Soul time to run out, and by the time your enemy broke your shield you were then able to immediately re-shield again. Just from observing a stranger I learned one of the most important lessons about the basic use of shields.
Likewise, reading the tooltip for Fade brought back all kinds of memories. In Vanilla it said: "Fade out, discouraging enemies from attacking you for 10 sec." Combined with the way that using this ability made you appear semi-transparent for a few seconds, I interpreted that as it giving me some kind of temporary stealth which would allow me to sneak past enemies at a closer distance than usual. When that didn't work, I mentally discarded the ability as useless.
Of course, the real purpose of Fade (and later versions of the tooltip reflected that) is to reduce your threat in combat. After I constantly drew healing aggro in dungeons, someone eventually asked me why I was never using Fade. I don't remember what I said, but probably something along the lines of: "Because it doesn't work!" But then I gave it another go in group content, and seeing mobs that were running towards me a moment ago turn right around and go back to the tank the moment I hit Fade was absolutely mind-blowing.
It's remembering things like that which enables me to have near infinite patience with people who play badly or just don't seem to get how something works, regardless of which MMO I'm in. They've probably got some perfectly valid reason on their minds for why they are doing what they are doing - even if they are "doing it wrong" - and it's probably something that I never even would have been able to come up with. That's the noob's prerogative.