If any mythology rules at having douchebag deities, its Greek Mythology. I like to chronicle the famous and obscure tales of douchebaggery that run throughout Greek Mythology. I would like to start with a fairly well known story, the story of Arachne and Athena.
Bitch are you challenging me?
Now for those who don't know this story here is the summary:
Arachne was a weaver, she boasted that she was better than Athena goddess of weaving, Athena gets pissed and challenges Arachne to a weave off, Arachne loses and in the end gets turned into a spider, forever weaving webs and hence why spiders are called Arachnids.
Now the douchebag moment happens after Athena wins, Arachne hangs herself in shame. In a rather a throw salt on the wound type act, Athena condemns Arachne, "So you shall live to swing, to live now and forever, Even to the last hanging creature of your kind." (Metamorphose, Ovid)
I'm not just happy enough with beating you, so I'm going to turn you into a spider
This is one of the few moments were I disagree with Athena's actions and an example of the problem that existed with the gods, they take minor offenses too seriously. Sure Arachne was being a boastful bitch, but Athena didn't have to get that pissed off about it and basically cause the mortal to kill herself. Now to be fair, other versions say that Athena took pity on her and turned her into a spider out of sympathy, but this version is prime example of douchebaggery in Greek Mythology.
And to close this here's Arachne in hell from Dante's Inferno
Arachne- first example of body horror?