I've done a fair few things in Warlords of Draenor, yet my favorite moment was probably near the beginning while we were still running Heroic Dungeons...
To clarify, in SBG Heroic, third boss, at ~40-50% health everyone died except me (Ret Paladin) and the tank (Prot Warrior). We still downed the boss. Somehow. Barely.
hehe... that reminds me how we killed heroic Heigan (Naxx) in WotLK with three people... me as DD, Druid Tank and Shaman-Healer... rest wiped doing the dance and Raid-Leader told us to go die, for a retry... we refused, and killed him within 10 minutes.