It doesn’t matter what’s making the stock market stall these days, Josh Brown writes in his Reformed Broker blog. What matters is that periods like this let financial advisors show clients what they’re really made of.

Brown says he doesn’t know why investors stopped buying every dip in sight last fall. Maybe currency bounces have tempered earnings for U.S. multinationals. Maybe falling crude-oil prices have triggered fears of deflation.

Maybe who cares? “The why isn’t terribly important to me,” he writes. “The what, however, is very interesting.”

Brown’s point: This new and dour phase of the stock market, characterized by bad-news headlines and finger-wagging TV pundits, “is actually a good thing for both the markets and for the professionals — like myself — who work here.”

In this view, “asset assigners” — Brown’s term for advisors, traders and fund managers — “cannot distinguish themselves when the only thing that goes up is the S&P 500.” “And it goes up every day, every week, every month of the year,” according to the blogger. “When investment profits become automatic for anyone who simply shows up, and diversification looks increasingly asinine with every quarter, we become almost useless — vestigial.

So far this year, however, profits “aren’t quite so automatic,” Brown writes. And the other day’s 300-point drop in the Dow “on the type of lukewarm data mix that used to be good for a hundo to the upside is yet one more piece of evidence that attitudes have changed.”

And that’s good, says Brown. “A much-needed dose of reality is being injected into the psyche of a hundred million investors,” he writes. And thousands of market pros now “have a reason to get out of bed again and do their jobs.”

Adds Brown: “As a professional, and as a person, I’m glad to see an environment that forces us to earn our upside once again.”