For me it happened when cip removed
pvp-enforced. Good old Inferna...
That partially did it for me. No more exp from PK. But the final blow came when they added the blessings (especially the 6th "pvp blessing"). Then it was no longer possible to benefit financially from PvP. Instead I had to grind PvE to get enough runes and mana pots for PvP. And the fighting lost it's charm too. There was no point in killing people anymore. I mean, why be a PKer if I couldn't get pots, runes, gear and level up from doing it? Especially when PKing made me so many enemies it was difficult hunting anything without getting chased down by all my enemies
But I will never forget that feeling when I found a perfect victim, around lvl 60-70 MS or ED, killing them and looting something amazing. Then fleeing across the map for what felt like an eternity while being chased by someone twice my level- only to run down a small hole where my friends were waiting, ready with SDs, fire elementals and demon skeletons. BAM!! ... Well, sometimes it ended with an UE, and all of us died. But I mean, some of the kills we got this way were
GLORIOUS!
When cipsoft removed those PvP features of the game, they basically removed the game I was playing. And I haven't found a game like that ever since.