Bad days. We all have them; some of us deserve them.

Here are five stocks whose naughty ways drew investors' scorn on Friday:

Company

Closing Price

CAPS Rating (5 max)

% Change

52-Week Range

Citadel Broadcasting (NYSE:CDL)

$2.40

**

(37.82%)

$2.31-$11.01

Leap Wireless (NASDAQ:LEAP)

$36.72

**

(36.80%)

$36.55-$99.04

Clearwire (NASDAQ:CLWR)

$13.49

**

(25.18%)

$13.03-$35.41

China Eastern Airlines (NYSE:CEA)

$85.00

**

(16.06%)

$17.50-$147.30

U.S. Auto Parts (NASDAQ:PRTS)

$7.27

*

(13.14%)

$5.07-$12.61

Sources: The Wall Street Journal, Yahoo! Finance, Motley Fool CAPS.

Naughty?
Well, OK, we can't exactly call these stocks naughty. But none of them get much love from our 74,000-person-strong Motley Fool CAPS community of amateur and professional stock pickers.

To the contrary -- when it comes to these stocks, CAPS investors have gone thumbs down more often than film critic Roger Ebert. They don't believe any of these stocks are worth owning, and that some may be worth shorting.

Which of today's candidates is worst? Read on, dear Fool.

Worse
We begin with Clearwire, which reported ugly third-quarter earnings last week and (gulp) the apparent end of a national partnership with Sprint Nextel (NYSE:S).

Clearwire and Sprint were aiming to build a national WiMAX network. (WiMAX is like Wi-Fi in that it is designed to broadcast the Internet wirelessly, but it does so over several miles instead of a few hundred feet.)

If that sounds bad, it's because it is. Without national WiMAX, Clearwire would have no way to create a critical mass for its services. Make no mistake; that's the vision here. CEO Craig McCaw, who helped to pioneer today's national cellular network, sees WiMAX in a very similar vein.

Now McCaw will have to start over. Yet I'll not completely side with the pessimists when it comes to this stock. Too many deep-pocketed investors have bet billions on WiMAX, and Clearwire, to see it fail now.

Worser
Next up is China Eastern Airlines, though U.S. Auto Parts Network CEO Shane Evangelist made it close with this ludicrous quote in his company's third-quarter press release:

I am excited to join the U.S. Auto Parts team at this pivotal moment. During the third quarter, U.S. Auto Parts demonstrated the ability to drive profitability. Couple that with an addressable market of over $90 billion, less than 3% online penetration and a very long tail product set, and we believe U.S. Auto Parts is well positioned to grow in a profitable manner. (Emphasis added.)

No hype there, right?

Wrong. U.S. Auto Parts Network operates a website for aftermarket auto parts. Profits were up during Q3, but free cash flow fell significantly. Orders and the conversion rate were also down. Some long tail, eh?

But China Eastern gets the nod here because, frankly, it's about time investors burst the bubble surrounding this regional airline. Here's why:

Return on Capital

Trailing 12 Months

2006

2005

2004

Total

(2.4%)

(22.3%)

0.8%

2.6%

Source: Capital IQ, a division of Standard & Poor's.

How this stock was ever bid up to 13 times its book value, when U.S. majors such as UAL barely manage two times book value, is a mystery to me.

Worst
But our winner is Leap Wireless, which last made our list of contenders a month ago. This time, it's down on a report that it will have to restate its financial reports going back to 2004, and that in doing so, it could be in violation of the terms of a $1.1 billion credit facility funded by Bank of America and a group of partners.

For now, the restatements would cost Leap Wireless $20 million in revenue and operating income -- hardly chump change for a business that booked just $30.5 million in operating income over the trailing 12 months, according to Capital IQ.

But it's actually worse than that: Leap is a serial cash burner, having last posted positive free cash flow in 2005.

Pity the poor investors who own this barking dog. Thanks to the restatements, they're now left with few options, chief among them being that peer MetroPCS (NYSE:PCS) still considers the newly troubled but vastly cheaper Leap as buyout bait.

That's possible. Then again, Donald Trump could co-star with Rosie O'Donnell in a Broadway rendition of The Apprentice.

The ugly truth is simply this: It's hard to borrow your way to growth, especially when creditors are in a position to demand increasingly generous terms, as Bank of America is now. Expect that they will, and invest accordingly.

Leap Wireless and its borrow-till-we're-bought management team ... Friday's worst stock in the CAPS world.

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See you back here tomorrow for more stock horror stories.