Ok, I freely admit, I remember every single thing about this issue. It's fairly impossible to forget unless you try to suppress it. This is the first issue where Gaiman no longer intimates darkness; he unleashes full horror.
You could almost read 24 Hours as a Greek tragedy, as one by one, the characters are punished for their hubris, and none more so than Bette, the waitress with whom Gaiman begins the story. She attempts to become a proto-Dream; all her customers are raw materials she moulds into stories. To Bette, her customers are more real as stories than as people.
She exerts artificial control over the stories; she ends them at happy points, not letting them carry on until death brings the inevitable end.
John Dee, in his horrifying way, acts with more honesty; he doesn't stop the story in the middle, death is the final destination of his own acts of creativity. We are introduced to his power in cinematic fashion; things start going very awry on the television. All we see of Dee is that he fingers Dream's ruby. It seems his power is very unfocused outside the diner, leading to random acts of depravity and madness, while inside the diner, he is the puppetmaster. And of course that's when things get creepy.
One interesting question is, at the point where people start revealing their "true selves," are they actually revealing themselves or truths or nightmare versions of themselves? The acts and prejudices described are almost too horrific for this random assortment of people to have possessed, and we do know that the ruby is the weapon of the Dream Lord, after all.
Next: Neil Gaiman forgets that John Dee is American, and I cannot concentrate on anything else because it's THAT annoying.