When I managed to complete my D2 set and all those "fast and short questlines".
First time I soloed Onyxia as warrior. Then MC. Then KZ. Then Pit of Saron dungeon. Bloodthirst spec op! No joking Blood DKs over everything.
When I started my tanking career in Ulduar. Well actually an achiev for healers. Props to them keeping me up in my 30%dungeon gear, 40% naxx10 gear and 30% naxx25 gear at XT and Iron Council.
Killing Atramedes after like 10 wipes the first try i'm on gongs while tanking.