"I had that terrible nightmare again."
Only it's not the worst one, is it? That paradise of cleanliness— everything immaculate, everything in groups of ten, everything completely identical— ruined by the piece of errant gum, carelessly left in just the right spot to hit his perfectly polished shoe... That's bad, yes. But it's not the worst.
The worst happens when he dreams of his beautiful, perfect Trudy, alive, smiling, by his side forevermore. The worst happens when he imagines what could have been and what never will be again. But that's not the nightmare.
The nightmare begins when he awakens.