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

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

Company

Closing Price

CAPS Rating

(5 max)

%

Change

52-Week

Range

Perini (NYSE: PCR)

$27.65

*****

(26.66)

$25.08-$75.43

A.M. Castle (NYSE: CAS)

$18.18

*****

(12.05)

$16.86-$38.10

Ionatron (Nasdaq: IOTN)

$2.79

*

(11.27)

$2.65-$6.57

AMR (NYSE: AMR)

$12.37

*

(9.18)

$10.95-$40.75

Advanced Micro Devices (NYSE: AMD)

$6.34

**

(3.50)

$5.31-$18.18

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 gets much love from our 81,000-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 they think some may be worth shorting.

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

Worse
We begin with Advanced Micro Devices, which after close yesterday reported a $1.8 billion fourth-quarter loss, $1.6 billion of which is attributed to a writedown of goodwill related to its 2006 purchase of graphics-chip maker ATI.

To be fair, AMD's results show improvement in margins despite a raging price war with Intel (Nasdaq: INTC). And CEO Hector Ruiz said the business is nearing breakeven after a string of steep losses.

Still, as an investor, I can't reward management for taking a blowtorch to shareholder capital. Especially when there's evidence aplenty that $5.4 billion was too much to pay for ATI.

Worser
Next up is Perini, whose developer defaulted on a $760 million construction loan for the Cosmopolitan Resort & Casino in Las Vegas. Quoting from yesterday's press release:

Perini Corporation confirmed that Deutsche Bank, on Wednesday, January 16, 2008 delivered a notice of loan default to the developer of the Cosmopolitan Resort and Casino project under construction in Las Vegas, Nevada. Perini is the general contractor for the project, which is scheduled for completion in December of 2009. Currently, Perini is in discussions with the developer and lender to facilitate an orderly continuation of construction of the project. Pending the outcome of these discussions, the Company is unable to determine the financial impact, if any ... At this time, construction work continues and all current amounts due to Perini have been paid pursuant to the terms of the construction contract. As of December 31, 2007, work remaining to be performed under the construction contract totaled approximately $1.4 billion. [Emphasis added.]

Translation: $1.4 billion worth of the $8 billion backlog we reported in November is now at risk. But don't worry, we'll be fine.

Worst
But our winner is American Airlines parent AMR, which instituted a fuel surcharge of $40 per roundtrip. Sort of. A company spokesperson told Reuters that the increase applies only to routes where American doesn't face competition from low-fare carriers such as JetBlue (Nasdaq: JBLU). Which is to say that this isn't much of an increase at all.

Rising fuel costs. No pricing power. Does anyone doubt that major airlines are among the worst businesses to invest in for 2008? Low-altitude flier AMR ... Thursday's worst stock in the CAPS world.

Do you agree? Disagree? Let us know what you think by signing up for CAPS today. It's 100% free to participate.

I'll be back Tuesday with more stock horror stories.

JetBlue is a Stock Advisor selection. Intel is an Inside Value pick. Try either of these market-beating services free for 30 days. There's no obligation to subscribe.

Fool contributor Tim Beyers, who is ranked 12,724 out of more than 81,000 participants in CAPS, hopes that Keith Olbermann doesn't mind the blatant theft of his "Worst Person in the World" segment from Countdown. Remember, Keith, imitation is the sincerest form of flattery.

Tim didn't own shares at the time of publication of any stock mentioned. Find Tim's portfolio here and his latest blog commentary here. The Motley Fool's disclosure policy thinks that cooked spinach is the worst veggie in the world.