Culture/Religion: based on fear and respect. Gods are very dangerous creatures, sometimes friendly, often not. Temples are the way to make contact with them... if not easier, then at least more concentrated in one place. Were it not for the temples, gods could be running amok among the people. Therefore, mortals have to keep the gods close to temples, entertained and worshipped. It doesn't make the bad ones any friendlier, though (and is no guarantee some won't go on trips now and then). Still, there have to be priests that are hardy men, able to survive the rigours of their position, get a sufficient number of worshippers to make the gods feel important enough, and mediate the contact between mortals and immortals.