Stupidity is contagious. It gets us all from time to time. Even respectable companies can catch it. As I do every week, let's take a look at five dumb financial events this week that may make your head spin.

1. It's a dirty Jobs but someone's got to do it
Shareholders bailed on Apple (Nasdaq: AAPL) on Tuesday, after it was revealed that Steve Jobs would be taking another medical leave of absence. The stock tumbled more than 6% at one point before winning back more than half of the intraday losses.

Didn't investors realize that COO Tim Cook did a more than capable job during Jobs' earlier absences? The steady flow of cooler Apple gadgetry continued -- and so did the earnings and stock gains. Jobs is an iconic figurehead at Apple, but he's not the only one responsible for its success.

That's not the only reason why selling Apple on Tuesday was dumb. The tech giant was set to report quarterly results later that night. Given that Apple routinely tops Wall Street's targets, why would someone dump the shares ahead of what was likely another blowout quarter? The few times when Apple's stock has sold off after a great quarter are usually related to huge runs leading up to the report. Tuesday's sell-off prevented that from happening.

What happened on Tuesday night? Revenue and earnings per share climbed 71% and 75%, respectively. Well done again, Cupertino.

2. Netflix misses the point
Logic is taking a holiday at Netflix (Nasdaq: NFLX).

You know all of those smartphone, tablet, and home theater apps that let Netflix subscribers stream flicks and manage their queues? Well, if a title isn't available in Netflix's digital library, members will no longer be able to request it in DVD form from their streaming devices. They will have to head over to a PC, log in, and tack the title onto their disc queues that way.

Really? Netflix is adding insult to injury by penalizing a member into doing extra work if the flick flicker hasn't inked a streaming deal for that movie. If anything, that's the best time to have that feature available.

Netflix can argue that it will make the app less confusing, but the company is probably covering up for the shortcomings of its limited digital catalog.

3. Palm someday
It's finally time for Hewlett-Packard (NYSE: HPQ) to get its webOS freak on.

HP is promising a series of webOS-related announcements on Feb. 9, so we may finally be ready for tablets, laptops, and new smartphones built on Palm's once groundbreaking operating system.

HP makes the "dumb" list because of the time that has been squandered since it forked over $1.2 billion for Palm back in April. Every quarter puts HP behind tens of millions of BlackBerry, iOS, and Android devices hitting the market.

A lot has happened in that time. Palm's webOS ability to multitask turned heads two years ago, but now it's just another wannabe platform that has faded in relevance. The competition is too entrenched.

HP obviously wasn't going to be able to reshape webOS a month after the deal was done, but it's just too late now.

4. One giant bleep for MannKind
Any diabetic tiring of needle pricks was cheering on MannKind (Nasdaq: MNKD) but was feeling the pain after shares of the biopharma upstart cratered yesterday.

MannKind was seeking FDA approval for an inhalable form of insulin called Afrezza. It was rejected for the second time in what one analyst is calling "the worst case scenario" for the once-promising treatment.

Investors knew that it would be feast or famine with MannKind. Nascent biotechs banking on a single breakthrough treatment are wild rides during the stiff approval process.

Afrezza isn't dead, but visions of inhalable insulin will have to wait for MannKind to complete two additional studies required by the FDA.

5. Oscar de la Trenta
I wonder what Morgan Spurlock thinks about coffee.

Starbucks (Nasdaq: SBUX) is introducing a new 31-ounce beverage size for its iced coffee, iced tea, and lemonade drinks. The new size is called trenta, which is Italian (and Spanish) for thirty. Why is a 31-ounce drink called thirty? Are these cups or Spinal Tap amplifiers? That's sort of dumb, but the real reason that Starbucks is being singled out is the audacity to belittle its beverage by serving them in gargantuan sizes.

Didn't Starbucks learn from McDonald's (NYSE: MCD) run-in with Spurlock for its super-sized offerings? Isn't 7-Eleven's Big Gulp the laughingstock of serving sizes? Why go that big, for a drink in a container that by some accounts has trouble fitting into a car's cup holder?

However, if we're going to engage in an arms' race, does Starbucks realize how silly going with 31 ounces is when McDonald's began selling a 32-ounce iced tea last year?

Which of these five moves do you think is the dumbest? Share your thoughts in the comment box below.

Apple, Netflix, and Starbucks are Motley Fool Stock Advisor selections. The Fool owns shares of and has written puts on Apple. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors.

Longtime Fool contributor Rick Munarriz is a fan of dumb and smart business moves. Investors can learn plenty from both. He does not own shares in any of the stocks in this story, except for Netflix. Rick is also part of the Rule Breakers newsletter research team, seeking out tomorrow's ultimate growth stocks a day early. The Fool has a disclosure policy.