Good ones whelpie!
Here's mine and I still can't forget it.
KQ Mara: All have died and disconnected leaving me (an archer) and two clerics to take on the first hurdle (Charismatic Marlone). The stronger cleric egged us on ("We can do this"), and she drops a tier 1 def and tier 1 evasion at my feet ("Use them"). Seeing this as my first big challenge, I buff up and hit Marlone with all my skills and Nature's Protection. Marlone promptly drops his attack and attacks both clerics, brutally killing them, and leaving me unharmed.
"Why'd you use that skill?" - She asks.
It was only then that I realized what Nature's Protection is for. I always thought it was some kind of curse buff on nearby enemies - or that it dealt damage. So I always used it in conjunction with my skills.
"sorry, I misclicked", was all I could come up.