A few things stand out, both from the start of WoTLK...
First, enchanting mats (forgot what their name was) in WoTLK sold on AH super quick for 20 gold a pop for the first month or so the expansion was out. I could make magic armor on my blacksmith for about 8 gold (Cobalt iirc), disenchant it on my warlock, and sell it for way more. Because I was on a popular server (Sargeras at that time), so many players... so much cobalt on the AH. I think over two weeks I made about 70,000 gold... like 1300 pure profit an hour. At that time, that was a HELL of a lot of gold. Blizzard hot fixed the issue during one of the nights... the cobalt armor or whatever disenchanted for about half the ingredients it did before. Good thing too because I got really sick of doing it.
Second, I had a warrior and only managed to grab Armageddon from Naxx (Betrayer of Humanity... I had loot rights on it for 15 or so Naxx25 runs and NEVER saw it drop. I NEVER saw it drop on ANY of my characters, and I probably ran Naxx 25 about 100 times). Anyways, I duo'd with a Resto Druid and did 2s... we were okay, but retadins and the new DKs were OP and, without BoH and the extra 5% crit, we couldn't climb too high. We stopped, and neither of us played our characters for a long time. When we logged back on, I was surprised to see that as still had placed high enough to earn titles.
Third, in Naxx 25, the safety dance guy... bunch of us died all over and we barely killed him, but then it awarded all of us the achievement for nobody getting hurt. It was pretty funny.