Show of hands: How many of you thought the world was ending yesterday afternoon?

OK, so I wasn’t exactly sprinting for the bunker. But watching the stock market drop 1,000 points in 30 minutes is enough to make anyone sweat a bit.

Financial cops are trying to track down the cause of the cliff dive. So far, the blame has been pinned on everything from technical glitches and human error to unrest in Greece and fear of yet another global financial crisis.

For me, it brought back uneasy memories of a recent Fresh Air interview with counterterrorism advisor Richard Clarke, who warned of a new age of cyberterrorism — a particularly disturbing thought, given the high-tech state of our financial system. That’s probably a little paranoid of me, but still …

Whatever the cause, one thing is clear: There are still a lot of raw nerves in the investment community — and still plenty of reasons to be diligent.

We’ve seen evidence that the economy is on the verge of recovery. Certainly that’s welcome news and reason for a bit of optimism.

But we can’t let optimism turn into complacency. There’s lots of uncertainty out there as well, and the Dow’s recent plunge is just the latest example.

Sitting back and waiting for the rebound is no longer an option. As Tom Hood says, we need to be taking steps to position ourselves to come roaring out of the recession, but we need to do more than that.

Folks are lining up to make wholesale changes to our financial system. Some of those changes may be long overdue. Others, though, will undoubtedly bring unintended consequences to the financial system’s good guys and the people they serve. That’s where our diligence comes in. It’s time to pay attention.

As Wall Street and Washington keep proving, we’re not out of this yet.