These three companies just didn't live up to Mr. Market's expectations last week. Sometimes an earnings stumble is a signal to sell, but digging in the dirt is also a good way to find turnaround candidates while they're getting beaten down.

... and a side of pain, please
I'll start this journey close to home. Orlando-based causal dining operator Darden Restaurants (NYSE:DRI) was supposed to serve up $0.50 of pro forma earnings per diluted share, but could only cook up a dish worth $0.42.

These numbers exclude the costs of working the newly acquired Longhorn Steakhouse and Capital Grille chains into Darden's operations. The $0.08-per-share shortfall was blamed on "a difficult consumer environment" and more expensive bread, dairy, and seafood ingredients.

Competitors like Ruby Tuesday (NYSE:RT) and Chili's operator Brinker International (NYSE:EAT) have seen their stocks fall right alongside Darden. It doesn't look like a great time to run a middle-class restaurant chain, in other words. On the flipside of that argument, all of their stocks look pretty darn cheap these days, after getting burned by price drops between 32% (Darden) and 63% (Ruby Tuesday) over the past year. Bargain hunters, feel free to sniff around your favorite casual eatery, looking for something fresh in the refuse.

Is there a pill for that?
Drugstore giant Rite Aid (NYSE:RAD) cited the same consumer apathy to explain last week's miss. The company was expected to take a $0.07 loss per share, but bled another $0.05 of unexpected red ink for a total loss of $0.12.

Rather than expensive milk, the second fiddle in this sad symphony was played by "a slow start to the cough, cold and flu season." We're too healthy, and the weather is too good, dangit! For the same reasons, Rite Aid pulled back on its guidance for next year.

But archrival Walgreen (NYSE:WAG) reported results the next day, beating estimates by a fair margin and sounding upbeat about its near-term prospects. That company is building tons of new stores to "meet the growing needs of an aging population," so Rite Aid's explanations start to sound more like excuses.

Yes, there's a complicated merger to work through, with hundreds of acquired Brooks Eckerd locations to integrate into Rite Aid's operations. But that doesn't slow down the flu season or consumer spending, does it? Get your story straight, people.

Bonus bonanza on hold
We already knew that Morgan Stanley (NYSE:MS) was facing a very rough quarter. The result? Say hello to a $3.61 loss per share.

You could say that the financial powerhouse suffered from the same ailment as the other two underperformers this week, only a step closer to the root of the problem. Two separate writedowns of subprime mortgage assets added up to a mind-blowing $9.4 billion, or $5.80 per share.

CEO John Mack effectively said "thanks, but no thanks" to any performance-related bonuses, because he felt responsible for the writedowns. How generous of him -- but I'd feel better if the board had told Mack that he just wouldn't qualify for any awards of excellence, rather than leaving it to him to decline the payouts.

Morgan Stanley can't sink much deeper into the subprime quicksand -- there's only $1.8 billion left of what was a $10.4 billion subprime portfolio at the end of August. The rest of the business looks healthy enough, though not quite on par with sector leader Goldman Sachs (NYSE:GS). Morgan Stanley's stock has taken a 35% hit over the last six months, and it's easy to imagine a serious rebound from these levels.

Happy holidays!
Some of these underperformers are victims of larger circumstances, while others might have only themselves to blame. It's up to you to decide which down-on-their-luck companies should be able to pull themselves up by the bootstraps, and which ones are stuck in the mud for real.

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Fool contributor Anders Bylund holds no position in the companies discussed this week, but he does harbor an abiding distrust of moose. The Fool has an ironclad disclosure policy, and you can see Anders' current holdings for yourself.