Well, if there's a WTFWHM there's also a WTFTANK:
-Unable to use combo's
-Unable to Flash/Overpower
-Unable to wind-up combos for upcoming adds
-Blows all/a bunch of CDs 5-10s before a pull
-Blows all CDs on one pack and has none for the next
-Prematurely pulls before the healers are done buffing (DPS don't need stoneskin! Right?)
-Pulls even though the scholar is applying adloquium/succor (look at the casting bar!)
-Loses agro on pull because not everyone was ready/still buffing up and blames it on others.
-Too hyper to stand still
-1 or 2 black mages in party: Still pulls one pack at a time
-Tanks that don't tank (Syrcus Tower scenario)
-Not tagging every mob they could have tagged while passing through them (flash/overpower or lobbing/tomahawking while running)
-Don't know what Provoke actually does
-Stays in field AoE damage (Tam-Tara HM second and last boss) <- yes, this DID happen
Did I forgot anything?
Edit: Actually, I did forget some:
-Tanks hitting slept mobs
-Thinks healers are only there to fill up HP bars - Healers can do more than just fill HP bars
edit2: GRAMMAR NAZI fix