Also a good thing about Ragnarok Online is that it's a 100% non-linear game, a lot of mmorpgs have you hop from zones to zones to level but in RO at any level there's at least a dozen different places where the xp is good and they're at all very spread out.
Also a ton of non instanced dungeons with boss at the end (who are almost always dead since it's no instand!)
Oh and RO is not really dependent on quests, now to level they implemented those kill x things quests to speed things up but they're far from necessary, got to 80 without them in like 3 days. There are other quests though, they give items, XP and give access to other locations and man some of them are long.
This one in particular is legendary : http://irowiki.org/wiki/Sign_Quest
Extremely long, reward is a pretty damn good item and access to one dungeon, let's just say that it's the dungeon it's the hardest to get access to!
Oh and the quests are actually interesting, skipping the dialogue is foolish.
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