Shattered Halls - mobs with scatter shot, fear, 50% Mortal Strike + 15% dmg taken debuff (fun without a mage or druid in your group)
Blood Furnace/Ramparts - trash with 360 degree cleaves, stuns, disarms, fears, etc. (cleaves nerfed at some point)
Mana Tombs - charge stuns, gouges, mana burns
Shadow Labyrinth - knockdown stuns, fears, mind control (number of trash packs were nerfed eventually)
Coilfang dungeons - fears, silences, mind controls
Arcatraz - aggro resets + random damage bursts, mind controls
People forget if you weren't losing control of your character as a tank you weren't in a TBC heroic