None. When I first started D&D, my good friend who got me into the game had read every Forgotten Realms novel in existence at that time. The task of running a game in Forgotten Realms with his daunting knowledge of the setting while having little to no knowledge myself was enough to put me off it.
For the next 25 years.
Mostly, this. In my case, I found the gray box to be a bit uninspiring, but unoffensive. My buddy liked it and ran one campaign set theoretically in Amn (or was it Cormyr?) that probably bore little resemblance to the book because of the insane Monty Haul nature of that campaign. I was the primary GM for the group and continued to work on my own, home brewed setting. Occasionally, I'd do something with Greyhawk, but mainly if it was just beer and pretzels. The other guy who did a lot of GMing also used a homebrew setting.
Sometime around 1990 (ish, it's been a while), I started to encounter more Realms-fans. That made me think that I should maybe look at the setting, again, since it was clearly the new Greyhawk/trade tongue. I found it somewhat... unpleasant. The amount of lore for the Realms was daunting, even at that point. There were also a few folks who couldn't just shut up about it, either, and most of them were canon nazis. I joined a couple of Realms groups, but often found them to be filled with players who insisted on nit-picking the GM with minutia about his setting mistakes or meta-gaming about various factions' motives. There was very little tolerance for my ignorance. The novels are (IME) universally too painful to force myself to read to gather the information contained therein. The details in the setting guides often feel like they're simply vanilla fantasy "turned up to 11" and the whole thing could be done in smaller scale with smaller organizations without losing anything beyond "it's world sweeping" -- of course, that could be due to the obsessive fan spew of facts I seem to run into more than the source books, themselves. During the early 1990s, TSR behaved rather poorly (Microsoft evil empire type behavior) especially if you were active on the Internet. One of these was an apparent pushing of the Realms into the forefront, especially if it meant replacing any personal touches Gary may have left on the game (i.e. Greyhawk). This didn't sit well with me, either.
So, the Realms came to represent a combination of rabid, fatbeard fans I didn't want to game with; truly horrible fiction; and vindictive corporate management. Regardless of the quality of the setting, itself, I'm not sure I'll ever be able to see the Realms as anything other than a blight.
One positive thing I'll say about the Realms: The production value of the game setting material has always been top notch. The gray box made me rethink some of my own notes on my home brew setting and the way I organized them. The 3e FRCS hardcover did the same thing, and I've repeatedly considered purchasing it for organizational guidance, even though I don't see me using any of the material. Even in 5E, the SCAG, while not revolutionary, is pretty much what I'd consider the "right" level of detail for a vanilla published setting.
I ran a Daggerford campaign years ago when the Under Illifarn module came out.
I remember the
Under Illifarn module and actually owned it. I remember absolutely nothing else about it, at this point. I do know that I used it and stole enough from it that I ended up bastardizing the name to "Ilfandar" to put into my setting. Note that I generally scrub any borrowed names like this and doing so has nothing to do with negative feelings about the Realms.
