Whether you admit it or not, we were all noobs at one point in time. A recent thread here about your first character made me think back to my early days of playing WoW back during mid-vanilla. I didn't know much about how WoW worked or really what it was all about when I purchased it on a lark one lazy weekend afternoon. I was immediately drawn to the Undead and ultimately decided on leveling an Undead Warlock.
I stuck to solo leveling all the way up to somewhere in my early 40s and then decided to branch out and try an instance. I found an Uldaman pug and we started making our way into the mine. We were on our way to the instance portal (you'll remember that the actual instance is quite a ways inside the cave) when suddenly a horde of scorpions or spiders (which I think I pulled) came rushing toward us. Someone in the group called out for me to use my AoE. I frantically searched my toolbars and finally said that I didn't know what AoE meant. Frustration growing, one of the party members explained it to me and said that I should have a spell called Rain of Fire. I searched once again and finally figured out that I never trained it because it didn't seem like a good spell. Although I don't quite remember, I'm pretty sure they insulted me in some manner and then disbanded the group shortly thereafter. Lol.
It pains me to look back on that knowing what I know about the game now. That experience is one of the reasons why I'm not *too* hard on noobs these days.
What is your worst noob moment?
Edit: Lol, I also remember the tank was calling me a "DoT machine" because I had no concept of threat and was constantly pulling off of him. Ah, good times.