I knew that after level 40 the game slows down. But killing trolls was extremely slow.
I was pretty fine with previous monsters. The quests to kill trolls were level appropriate, I wasn't lost and trying to kill to high monsters. I didn't accidently replaced my +6 gear to random drops, I checked it dozen times. I tried to optimize my skills to squeeze out a little DPS increase and I found a guide.
Only this guide informed me about "states". For example a target turning away is in "back" state and receive extra damage. I usually opened with Celestial spear, because it gives crit buff and it knocks down the targets and it's easier to place Sword of Judgement on them if they aren't moving. What I didn't know, because the game never told me that Sword of Judgement is a "down" attack, therefore does extra damage on knocked down targets.
Trolls are immune to knockdown, which seemed to be only an inconvenience, while in reality it cut my DPS to half. If I knew about "down attacks", I never went anywhere near them. After I learned it, I went on and in the Abandoned Quarry I was fine again.
Down with bad NPE in BDO! Down with it!