Stupidity is contagious -- even respectable companies can catch it. Let's look at five dumb financial events from last week that may make your head spin.

1. The camera's on your head
It isn't a surprise to see six underwriters that took GoPro (NASDAQ:GPRO) public last month initiate coverage last Monday. That's just how things work. If a debutante offers you a shot at scoring some underwriting royalties on a hot deal, you're going to return the favor. However, it's pretty telling that all but two of the six analysts went with neutral ratings on the company behind the popular wearable cameras. 

The reason for the ho-hum underwriter reactions is that they took GoPro public at $24 four weeks ago. It's hard to be bullish when the stock kicked off last week in the low $40s. However, Piper Jaffray and JPMorgan bucked the trend, offering bullish ratings with price targets of $48 and $51, respectively. 

That may not seem so bad, but then you have to wonder why they helped take GoPro public at $24. If the price target is going to be a double, you owe it to the new public company not to let them leave so much money on the table.

2. A matter of Herbalife and death
Bill Ackman has a flair for the dramatic. Shares of Herbalife (NYSE:HLF) tumbled 11% on Monday after Ackman went on CNBC, promising to expose the distributor of nutrition products as "the largest public fraud" on Tuesday.

Ackman's been blasting Herbalife since shorting the stock in late 2012, arguing that it's a pyramid scheme rewarding its sales force more for recruiting others than for actually selling merchandise. 

"This will be the most important presentation that I've made in my career," Ackman promised. "We won't disappoint."

Well, they did disappoint. Ackman's ballyhooed presentation failed to woo the market, sending Herbalife shares soaring on Tuesday.

3. Shifting into reverse
General Motors (NYSE:GM) can't seem to catch a break. The iconic automaker is recalling another 717,950 cars last week to correct a half-dozen safety issues.  More than half of those recalls are related to a possible problem with a bolt adjusting the height of the front driver and passenger seats.

This isn't as bad as the ignition switch problem that has resulted in several fatalities, but the bolt problem -- not to be confused with GM's Volt problem -- has already been tied to at least three injuries. This now finds GM closing in on 30 million cars being recalled this year. It's great to see GM owning up to earlier flaws, but at some point all of this is will make it hard for drivers to trust the brand.

4. Tuning out
Pandora (NYSE:P) didn't live up to expectations, and it can only blame itself. The leading music-streaming service stopped providing monthly usage metrics in May, and perhaps we know why. 

Pandora revealed that it closed out the June quarter with 76.4 million active listeners, fewer than the 77 million it was entertaining during the month of June. It also announced that it served up 5.04 billion hours of content during the quarter, but subtracting the April and May tallies results in a sequential dip during June.

Now investors will have to wait three months to see whether Pandora is continuing to fade in popularity. That is not what the company wants, but it put itself in this position in more ways than one.

5. Bored of directors
There was a board shakeup at American Apparel (NYSEMKT: APP) last week. That's good. American Apparel is a struggling mall clothing retailer that could use some fresh thinking to get out of its rut. 

However, one of its boardroom additions is RadioShack CEO Joseph Magnacca. True, Magnacca has only been at the helm of the fading consumer electronics chain for 18 months, so you can't pin RadioShack's ill-advised shift to mobile products on him. However, RadioShack is showing no signs of turning the corner since his arrival, and the stock has shed more than two-thirds of its value since his arrival. He should be focusing on RadioShack, and American Apparel needs someone that's been more successful.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.