I, too, found myself in a 'love' triangle at like... 13. But I didn't know it was a love triangle - I was in it for the friendships and suddenly, hentai. I don't miss it XD
I do miss:
Guilds - I was in a huuuge 'wolf' guild with a heavy focus on RP. Never RP'd myself (maybe once, it was a sad attempt), but reading the message board on Friday nights was awesome, my guildies were a creative bunch!
Plots - Boy, do I wish we still had something to do on the site. I remember eagerly anticipating the next event, knowing it will be just as fun and rewarding as the last. These days, anything that's rolled out is either broken, unreasonably labor-intensive, or both. Usually both.
People - I miss the old community in general. People weren't as cut-throat and competitive, at least not in my 'circles'. I've met so many amazing people, all of whom have since quit, and sometimes neo just feels really lonely!
Edit: OMG YES KEYQUEST. I've pulled all-nighters for that shit
Edit 2: Snow faerie quests. I don't know why, but I had a BLAST doing those. It's been years since I've even thought of the snow faerie