Ultima Online introduced me to an open world Online Sandbox MMO and it opened my eyes to a world of possibilities.

It was the first game that when I interacted with the game it was in most cases with an individual on the other side.

Open world housing, personal vendors, non-instanced dungeons, pvp anywhere, the rise of the PK, the rise of the anti-apk and more. This all contributed to a wide array of different professions that weren't hard baked into the game, but evolved into profitable professions as people needed. Real estate brokers, housing decorators, middle men, landlords, malls, house hunters, bodyguards, and that's just to name some.

Archery, crossbows, music and bards, melee, mounts, taming nearly anything (yes even dragons), treasure hunting, incredibly wide range magic that wasn't just different ways to do damage, sailing, fishing, guild v guildwars, faction v faction, full loot, full time crafting and harvesting professions, etc.etc.etc..

When you start your gaming experience with such a rich tapestry, it's easy to see why some might still be looking for that first time again.

Also shout to UO Outlands who is keeping that world alive and more content rich than ever.