NEW YORK (CNN/Money) - Wall Streeters mostly love Halloween. What's more fun than putting on one of those swanky new Dick Grasso masks, or maybe that old Henry Blodget costume, and making the rounds.

But late at night, when they're up in their rooms fighting against that sugar high and the wind is blowing and the branches of that old elm are rubbing up against the side of the house -- well, then Wall Streeters start thinking about all the things that could go wrong. And they get very frightened.

Have a kid brother who works on Wall Street? Halloween night, after you've tricked him into trading all his Snickers bars for your Trident (to do this, tell him that Trident "has mo'"), here are some things you might do to scare him silly:

Justin Lahart, senior writer at CNN/Money, talks about how to frighten the Wall Streeters in your life. Play video (Real or Windows Media)

The best way to do this is probably to open up to the article Warren Buffett wrote in the latest issue of Fortune. It's got some nice graphs of the swelling U.S. trade deficit and of all the U.S. assets that foreigners now hold. Point out that the current account deficit is north of 5 percent -- which for any other country would be a sign of imminent currency collapse.

Point out that late economist Rudi Dornbusch -- best known for his work on exchange rates and overshooting -- always said that currency imbalances, once they corrected, always corrected more violently than people supposed they would. Tell him that Buffett has now, for the first time in history, moved some of Berkshire Hathaway's portfolio into foreign currencies.

Remind him of what happened the last time he didn't listen to Buffett.

And then suggest that maybe his perception that all the corporate shenanigans of the past haven't quite gone away yet. Note that reform on accounting for employee options is getting pushed back again. Ask him if he has any idea, really, what's going on at Fannie Mae. Point out that companies have got back into the habit of writing off "one-time items" to put a shine on earnings that really aren't there.

Suggest that there really isn't a new conservatism afoot in corporate boardrooms at all. Instead, it's just the same old hucksters pretending to be conservative. CEOs are master salesmen, after all -- just look at the ridiculous amounts they (still) get paid.

Once a trick and cheater, always a trick and cheater.

Remember all that excitement about third-quarter gross domestic product Thursday? It grew at a 7.2 percent annual rate -- the fastest pace since 1984. So where, pray tell, are all the jobs? With all that growth, you'd think that companies would be hiring by now, but instead we're in the midst of the longest post-recession job slump in history.

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The only thing that's given consumers the wherewithal to keep on spending like they have is a raft of money generated by tax cuts and the cash they got refinancing their mortgages. In other words, if the government and they hadn't gone further into debt, we'd already be sunk.

But now the tax-cut and mortgage-refinancing effects are fading. People say that business spending will make up the slack, but that's seems tough when you remember that consumer spending accounts for 70 percent of GDP.

...because it sure seems like investors are smoking something. Just look at the stocks that are up the most this year -- Dynegy, Corning and Williams are all up over 200 percent and Avaya is up over 400 percent. Weren't these the same companies that people got burned on so badly last time? And all of them show losses for the past year.

Valuations in general look steep. The S&P 500 trades at a historically rich 21 times earnings -- if you use those bogus, before-write-off earnings known as pro forma. If you use earnings under generally accepted accounting principles you get a PE of 28. The average PE on a GAAP basis since 1989 has been 23.5 -- an average that includes the recent bubble years.

Disturbingly, it seems like a lot of investors these days are merely in it for the trade, believing that this time around they'll get out before things go wrong. That's known as the greater fool game -- you're betting that there is going to be some greater fool to buy a stock at an even higher price from you. It's often a recipe for disaster.

A Wall Streeter's worst fear: That you get overly focused on all the things that could go wrong, and stocks rocket higher.

You can try to play catch up by loading up on dangerously volatile stocks, or you can stick to your guns and hope the market comes down so you can get back in. But if you blow your year, you can forget about getting much of a bonus and maybe you can forget about even having a job.

Hey Wall Street ... boo!