The amount of times I've popped off a lustrate on myself due to fail targeting the tank. Dropping a sacred soil AFTER the trial wide AOE has hit and being like...oh right BEFORE.

And by far the dumbest....

Getting my scholar to 60 and taking it into end game raiding content.... without having done any of the 50-60 job quests (no emergency tactics, no indomitability, no Broil...)