Fallout 2/Fridge

Fridge Brilliance

 * The world of Fallout 2 is unlike most sandbox games in that it actually has an infrastructure that doesn't conveniently revolve around you. In fact, many of the game's quests relate directly to this infrastructure and lets you turn it towards drugs, slavery and general debauchery, lead it into a fragmented prosperity, unite it all under the banner of the NCR or even destroy large chunks of it.
 * To elaborate on this infrastructure, most of the land's food comes from the large Brahmin herds and farms of Modoc (whose prosperity you can restore, leading to more food, or you can let stagnate, meaning many areas are hard hit) and NCR's own stocks. Vault City and NCR are responsible for training and supplying the majority of the doctors. New Reno is the drugs, booze gambling capital, The Den is home to the biggest slave organisation, Gecko can provide power, and NCR and Vault City have self sustained power. Vault City can give medicine and tech, Broken Hills' uranium mines provide the slugs for the power stations and Redding mines gold which backs the land's economy. You can manipulate the faction's leaders, each of whom has their own ideas of how to further their settlement, and through this the geo-political situation as a whole. Plus, you can encounter and even work for the caravans that carry the land's goods about.