I have learned one thing—and maybe just the one thing—about the nature of the universe: Sometimes you will see a wet floor. Sometimes you will see a sign that says CAUTION WET FLOOR. But only rarely will you see both of them at the same time. The next time you see one of these two things, check around for the other and notice how seldom you'll find it. Shouldn't they go together? You'd think. But cosmic, unknowable forces conspire to keep them apart.

Of course, every rule has its exception, and this rule's is at a local Wal-Mart, where you'll find a wet spot on the floor and a CAUTION WET FLOOR sign close by. You'll find both if you go there right now, in fact, because this Wal-Mart has had a wet spot in the same place on the floor perpetually since the store opened many months ago. For all I know, the sign may have been permanently bolted in place, a proud monument, sign and puddle paying eternal tribute to one another.

The same principle is at work in the daily radio traffic report. If you're sitting in a traffic slowdown and you here a report on the radio, it will not mention the jam you're stuck in. If you hear a report of a traffic jam in an area where you happen to be driving at that moment, you will see no sign of trouble. If a report somehow manages to reach the air while the slowdown is still in effect, you will hear it too late to avoid the problem.

Timing isn't everything, but it's most things.