I kinda get that greek gods are fickle, spontaneous and temperamental because they are personifications of larger-than-life stuff
But an in-myth explanation to their emotional incontinence could be that a majority of them are literal incest babies. It is like that whole Habsburg thing.
I present to you; The Olympian Temper Syndrome.
I always find it funny in hindsight where the hubris tales of Greek mythology were supposed to be lessons in humility for humans who reached for more than they could handle... But some of them are just the gods catching Ls non-stop and the humans can't be blamed for the gods being worse at the things they're supposed to be good at. Like the story of Arachne competing with Athena in a weaving contest; with nothing better to do but torment a poor lowborn Lydian girl who boasted her weaving skill was superior to all - even the gods, Athena challenges Arachne to a weaving contest in the disguise of a mortal.
Athena weaves a tapestry showing the gods punishing the mortals for their hubris. Arachne weaves a tapestry of all the times gods appeared before mortals in disguise, decieving them and ruining their lives just to get what they want. Athena, goddess of wisdom, in her disguise she is using to deceive Arachne to get what she wants, then reveals her disguise (lol) and unable to find any fault or criticism of Arachne's perfect tapestry, grabs her weaving shuttle, smashing Arachne on the head four times. Unable to cope with the pain, Arachne kills herself by hanging - and out of "compassion" wise Pallas Athene uses witchcraft to transform Arachne into a spider
Pallas could not blame that work, nor could Envy censure it. The yellow-haired Virgin grieved at her success, and tore the web embroidered with the criminal acts of the Gods of heaven. And as she was holding her shuttle made of boxwood from Mount Cytorus, three or four times did she strike the forehead of Arachne, the daughter of Idmon. The unhappy creature could not endure it; and being of a high spirit, she tied up her throat in a halter. Pallas, taking compassion, bore her up as she hung; and thus she said: “Live on indeed, wicked one, but still hang; and let the same decree of punishment be pronounced against thy race, and against thy latest posterity, that thou mayst not be free from care in time to come.” After that, as she departed, she sprinkled her with the juices of an Hecatean herb; and immediately her hair, touched by the noxious drug, fell off, and together with it her nose and ears. The head of herself, now small as well throughout her whole body, becomes very small. Her slender fingers cleave to her sides as legs; her belly takes possession of the rest of her; but out of this she gives forth a thread; and as a spider, she works at her web as formerly.
Literally petulant overpowered children losing the argument every time and in their implike seething deciding "WELL I DON'T LOSE BECAUSE I KILL YOU I WIN"