The Terry Pratchett theory of gods is that all it takes is belief and prayer, and you can make a god out of anything.
Many cultures have also held that people of great fame and/or power can achieve godhood simply by people speaking their name with great emotion.
Unfortunately for That One Guy, a Vietnamese peasant who died in a freak water buffalo accident several decades ago, this is very much the truth. So many have said his name in a state of wonder and consternation over the ages that he has been become elevated as one of the highest deities of personal relations. But see, poor humble That One Guy never wanted to be a god, much less a god based around the concepts of obscurity and forgetfulness. Every time you forget the name of somebody but insist on referring to him in conversation, or gossip about somebody you've never been formally introduced to, you simply add to That One Guy's misery.
So please, for His sake, remember the names of your casual acquaintances, speak only of those whom you know, and say a silent prayer of sympathy for That One Guy... just don't mention him by name.