There are more serious games that had lots of tables, like Rolemaster, and basically the idea is for the game system to generate a wide variety problems and situations for the players to deal with, in combat but also in encounters and such. This takes some load off the GM by providing a lot of variety without preparation, but also because these outcomes are generated by the rules, the players can't claim the GM is picking on them by imposing nasty consequences arbitrarily. It's just one school of game design though.