I honestly just want someone to came back and describe cool parts of the setting again.
At its heart Greyhawk is very pulpy. The Bright Desert is especially pulpy.
The Bright Desert is an anomalous region (as in you shouldn't have a desert next to a cold mountainous area) that is the result of an evil wizard-king trying to use the Crown of Scorpions, an artifact tied to Tharizdun the Destroyer, to ensure his rule. Instead it turned him and everyone around him into man-scorpions (like in the Rock movie, but this was written years before that) and the formerly feritle area into a massive desert. There are also desert centaurs, ghosts, norkers, dragons, ancient Flan (the Flan are the celtic/aboriginal inspired original inhabitants of the Flanaess) ruins and so on roaming the region, as well as desert banditos. Right on Greyhawk's doorstep.
Of course the Bright Desert becomes really interesting when Rary the Traitor moved there after he was caught trying to explode the signing of the Greyhawk Wars peace treaty. He transplants a lot of his allies with him to the desert, including some desert nomads from the other side of the map. He wants to get a hold of said crown and claims it's to undo the curse on the region. Unfortunately his surname is "the Traitor" now, so make of that what you will. Also the Crown might be one of the few bonds that prevents Tharizdun the Destroyer from escaping his prison and laying waste to the Oerth so again - would you trust someone called The Traitor with one of the nuclear codes?
Last time it took three days for someone to tell me about the Bright Desert in a way that made it interesting. Then whenever I try to defend the setting due to that, I can only find sources designed to act a heavy-duty anesthetic.
There are 3 time periods that Greyhawk supplements used to come in.
Classic Era (576-582 CY). This is the era in which all the classic Dungeons and Dragons adventure modules are set like Temple of Elemental Evil etc. The ones WotC
really seems to like repackaging.
Greyhawk Wars Era (582-585 CY). Takes place immediately after the Greyhawk Wars (though you could set it during if you wanted). The tone is far darker and more desperate than the classic era and adventures set in this time focus on fending off evil and keeping the flame of hope and goodness alive.
Renewal Era (586-591 CY and beyond). The forces of good start to push back the tide of evil towards a fragile equilibrium between light and dark.
Problem is Greyhawk fans are dogmatic. None of them even agree how many "time periods" there are. Some swear by Gygax's original boxed set, some like From the Ashes, very few prefer the subsequent era which tried to dial the doom back a little (though there were still some places like Onnwal where the Wars hadn't ended every nearly a decade later).
I'm a big fan of the post-Wars period where the setting became less vanilla D&D and more British Grimdark fantasy. Entire nations were destroyed by magic and are now smouldering ruins, the evil powers were checked but have made gains, loads of demons and devils are swarming the invaded realms and some of the good countries are now bankrupt, paranoid of strangers and prone to the odd peasant uprising because they cannot feed their people.
The Circle of Eight by this point is the Circle of Five as Rary managed to kill 2 of the members before having a final meeting with HR.
There's a thing called the Doomgrinder introduced - it is a mysterious stone windmill no-one knows who built it.
"Legend has it that the Doomgrinder is counting down the years to a major cataclysm as great as the Invoked Devastation. One of its sails is now but two degrees away from its zenith, and some say that when that sail moves to that point, the end will be at hand."
This era is much more lore/sourcebook heavy and far less module heavy (in a good way - the author they had writing the supplements could pack in a lot of good stuff). It focused a lot less on Greyhawk City and more on the outer realms of the Flanaess. There is the odd gem of a module like Road of Skulls where you have to infiltrate Iuz's capital to rescue one of the old rulers of the Flanaess that Iuz captured when he steamrollered through the Shield Lands. It's pretty dark given that Iuz builds his roads out of biodegradable materials, but not in a good way.
you find out that pretty much every named character in the D&D cannon is from here and the D&D villain everyone cares about comes from here,
Assuming you mean Vecna, yes he first appeared in a Greyhawk module where you got to play as the Circle of Eight for the first five minutes... before Vecna kills them all and you get your real characters. This is also an excuse for why the Circle were out of play in the Wars - Mordenkainen had to clone them. As for the Circle members killed at the end of the war, well Rary the Traitor had his allies get rid of all their cloning facilities.
I think he was pretty decisively defeated in the adventure, but because folk liked him he got to become a god and star in Ravenloft and Planescape adventures. Something similar happened to the lich Aza'lin who popped up in Ravenloft.
but no one seems to actually want to talk about that stuff, only that there's no Dragonborn allowed and some race supremacists are all brothers or something.
Folk round here really love their Dragonborn.