Stupidity is contagious -- even respectable companies can catch it. As we do every week, let's take a look at five dumb financial events this week that may make your head spin.

1. What can brown do for you?
This holiday shopping season was botched by online retailers, and United Parcel Service (NYSE:UPS) is taking the fall.

UPS isn't the only parcel delivery specialist that failed to deliver many gifts ahead of Christmas, but it's the one receiving most of the negative mentions for being slammed with last-minute orders that failed to make it to their eventual destinations by Christmas Eve.

This was going to be a challenging season for retail in general, given the late start and Cyber Monday being pushed into December. However, UPS and its package-toting peers should have been more prepared.

2. Target practice
Things just aren't getting any easier for Target (NYSE:TGT) after a security breach that exposed the credit and debit card information of 40 million transactions to hackers. Reports seemed to suggest that even offering 10% discounts this past weekend wasn't enough to drum up a spike in plastic-protecting shoppers, and Monday the cheap chic retailer revealed that the Department of Justice is investigating the situation. 

Now at least one senator wants to see what can be done about making retailers more liable for these lapses. Even if that doesn't happen, shoppers are likely already punishing Target for the country's second-largest security breach. 

3. Grimace isn't just a McDonald's character
McDonald's (NYSE:MCD) is finally shutting down its McResource Line website for employees after yet another publicized blunder. 

This week's gaffe was a claim that the internal site was recommending employees avoid fast food because it could make them overweight. The world's leading restaurant chain counters that the suggestion was taken out of context, but it's just one more embarrassing incident that has provided ammo to activist groups urging the chain to provide better pay for its employees.

Earlier McResource Line gems included tips for tipping au pairs and massage therapists, as well as budgeting advice that was out of touch with reality. Mickey D's will keep an internal phone line intact to assist its employees -- and that's a good thing -- but it was getting too easy to pick on McDonald's, despite the website's best intentions.

4. Your suitcase will pay more than you
Delta (NYSE:DAL) is going to pay for a glitch on Thursday morning that resulted in folks booking flights for as little as $5 before taxes and fees. Delta temporarily shut down its site to fix the error, but not before countless opportunists were able to book cheap flights.

Delta's doing the right thing. It will honor the fares for those who were fortunate enough to book them. It will just cost Delta on the bottom line. 

5. Citron strikes again
Shares of Textura (NYSE: TXTR) tumbled 17% on Thursday after becoming the latest target of Citron Research's scathing corporate critiques. Citron alleges (link opens PDF) that the recently public provider of cloud-based enterprise software solutions for the construction industry is worth far less than its current value.

Citron accuses the CEO of a shady past, points out potentially problematic relationships between executives and the underwriters, and calls out Textura for having to revise original prospectus claims that it had a high client retention rate and was seeing growing global demand for its software.

Citron isn't a kiss of death. There are a few companies that have effectively countered the argument and won for investors over time. However, it's always rocky when the accusations start to fly.