The Spy in the Elevator by Donald E. Westlake

When the elevator didn't come, that just made the day perfect. A broken egg yolk, a stuck zipper, a feedback in the aircon exhaust, the window sticking at full transparency—well, I won't go through the whole sorry list. Suffice it to say that when the elevator didn't come, that put the roof on the city, as they say.

It was just one of those days. Everybody gets them. Days when you're lucky in you make it to nightfall with no bones broken.

But of all times for it to happen! For literally months I'd been building my courage up. And finally, just today, I had made up my mind to do it—to propose to Linda. I'd called her second thing this morning—right after the egg yolk—and invited myself down to her place. "Ten o'clock," she'd said, smiling sweetly at me out of the phone. She knew why I wanted to talk to her. And when Linda said ten o'clock, she meant ten o'clock.

Don't get me wrong. I don't mean that Linda's a perfectionist or a harridan or anything like that. Far from it. But she does have a fixation on that one subject of punctuality. The result of her job, of course. She was an ore-sled dispatcher. Ore-sleds, being robots, were invariably punctual. If an ore-sled didn't return on time, no one waited for it. They simply knew that it had been captured by some other Project and had blown itself up.