Building. And that's getting harder to enjoy with limitations on farming, issues with inventory space (around 2000 items it gets frustrating), and lack of recent/fresh interactive furniture. That botany place was a neat concept tho..!
I haven't played much since 2008ish. I enjoyed quests and exploration, and then I enjoyed scripting things and making quests, but the serverside development requirements and limitations of the NPC server at the time kind of held a lot of development back compared to say overworld development (which is mostly cordoned off right now).
Tried to get into towering with the new guild system, but it’s less fun than i remember it being before. Now I just log once every few days to chill outside mod for 5-10 mins and pk/pm friends. I’ve got a weird hate for the game after like 10 years now so that kinda sucks.