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

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

Company

Closing Price

CAPS Rating (out of 5)

% Change

52-Week Range

Smith Micro Software (Nasdaq: SMSI)

$5.62

****

(12.7%)

$5.33-$21.20

ITT Educational Services (NYSE: ESI)

$54.02

**

(7.6%)

$53.40-$131.82

SumTotal Systems (Nasdaq: SUMT)

$4.35

***

(7.3%)

$3.81-$8.95

Aventine Renewable Energy (NYSE: AVR)

$6.52

*

(6.1%)

$6.37-$20.85

Northwest Airlines (NYSE: NWA)

$15.86

*

(2.5%)

$10.70-$26.50

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

Naughty?
Well, OK, we can't exactly call these stocks naughty. There are days when five-star winners and newsletter recommendations appear here.

But, if you're an investor, you'll have plenty of bad days. The trick is to avoid dating -- or, worse, marrying -- your losers. That's why I listen when our 84,000-person-strong Motley Fool CAPS community of stock pickers speaks with a poor rating or a negative pitch. You should too.

Thus, here is today's list of the worst stocks in the world.

Worse
We begin with ITT Educational Services, which last month announced new funding options for those who are about to be stiff-armed by student loan specialist SLM Corp. (NYSE: SLM), otherwise known as "Sallie Mae."

The implications of that news -- fewer enrolled students, I suggested -- became clear yesterday when management cut 2008 guidance. Executives now expect $4.10 to $4.60 per share in full-year earnings, down from an earlier estimate of $4.50 to $ 4.60 a share.

Worser
Next up is Northwest Airlines, which may be unable to reach an accord with Delta Air Lines (NYSE: DAL) because of labor problems.

According to news agency Reuters, the 11,000 or so pilots at both airlines have yet to agree on terms for a combination. That's critical. Each carrier possesses what's called a "seniority list." The most experienced pilots on those lists get the highest wages, the best benefits, and the best routes.

If they can't agree on a deal, it's probably because Delta's pilots -- since they're employees of the acquiring company -- are demanding that Northwest fliers move to the back of a combined seniority list. They won't do that willingly.

But you knew that, right? Years after US Airways combined with America West, labor fights persist.

Worst
But our winner is SumTotal Systems, which revealed a new executive bonus plan on Monday night. Find the details here.

There's a lot to like about the plan at first blush. Executives are expected to produce outsized results in bookings, revenue, and operating profit. Payouts, meanwhile, only come to those who achieve 70% of plan for operating profit, or at least 50% of plan for operating profit, and 90% of plan for bookings.

Much as I'd prefer to see zero compensation for anything less than 100% of plan, I have to admit that, on the whole, I've seen deals far more generous -- and unfriendly to shareholders -- than this one. What troubles me, and why SumTotal earns today's top spot, is this line:

In the event of the failure to achieve the thresholds set forth in the Plan, the Chief Executive Officer or in the case of Section 16 Officers, the Compensation Committee, may in its sole discretion, approve payment of bonuses.

Translation: Real accountability is for sissies.

SumTotal and its totally unacceptable bonus plan ... Monday'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 tomorrow with more stock horror stories.