TV advertising is in the midst of rapid change as advertisers re-allocate their budgets to maximize the full spectrum of channels from broadcast to social media. But whether an ad is showcased on prime-time TV or goes viral on YouTube, two constants remain: (1) a well-crafted ad hit can be transformational for a company’s brand, and (2) A highly public miss can skunk up the brand’s image (and sales) even faster.

TV ad blunders are nothing new, but the prevalence of social media and the impact of viral videos ups the ante for companies and their ad agencies. But in their zeal to gain brand recognition through buzz, companies sometimes end up angering or offending the very people they’re trying to convince to try their products.

For example, Guido Barilla, chairman of the Italian pasta brand of the same name, recently discovered that fact the hard way after he said he would never do a TV ad that featured a same-sex family.

Here are five memorable “ads gone bad” that companies — and their ad agencies — probably wish they could take back.

Groupon

Ad Title: “Save the Money — Tibet”
Agency: Crispin Porter + Bogusky

This ad for the local commerce deal site made its debut in Super Bowl XLV — and as with most organizations that pony up big bucks for commercials at America’s Game, Groupon (GRPN) expected to get a very big bang for those bucks.

Crispin Porter + Bogusky — the same agency that brought back Burger King’s (BKC) creepy, masked King — kicked off this ad with actor Timothy Hutton discussing China’s human rights abuses in Tibet.  The ad packed a dynamite punch all right, but it blew up in GRPN’s face.

That’s because in advertising as well as football, how you finish matters. Hutton’s socially conscious spot veered off track into a rave about Groupon’s great deals on fish curry at Himalayan eateries. Viewers were shocked and offended by the ad, which many believed to be mocking the plight of Tibetan refugees. Four days later, the ad was history.

BP

Ad Title: “A Message from Tony Hayward”
Agency: Purple Strategies

BP’s (BP) $50 million ad blitz to improve the company’s image two months after the Deepwater Horizon rig exploded was a colossal failure.

Crisis communications require a certain finesse — that’s why BP bypassed Ogilvy & Mather, its agency of record, and opted for political heavyweight Purple Strategies. But time is a critical component of success, and the apology ads began airing six weeks after the disaster killed 11 workers and began spewing 100,000 barrels of oil per day into the Gulf of Mexico.

Another misstep: the choice of BP CEO Tony Hayward, who just days earlier had muffed an apology for the “massive disruption” the spill caused by saying “There’s no one who wants this over more than I do. I’d like my life back.” The spots further enraged Gulf Coast residents, who would rather have seen that $50 million channeled into cleaning up the spill, rather than trying to buff up BP’s tarnished image.

Taco Bell

Ad Title: “Veggies”
Agency: DraftFCB

At a time when nutritionists are up in arms about the evils of fast food, it’s always good to take an extra moment to vet TV ads that could be misunderstood. Unfortunately for YUM Brands’ (YUM) Taco Bell and creative agency DraftFCB, this ad admonishing playoff party-goers who bring veggie trays to game-day gatherings turned out to be a costly fumble.

Taco Bell’s ad, which aimed to promote its variety taco 12-pack, said bringing a veggie tray to a party was like “punting on fourth and one”. However, the advertisement came up well short of a first down.

The company scrambled to pull the ad after the Center for Science in the Public Interest urged people to rail against the spot on Twitter. Although CSPI thanked Taco Bell for pulling the ad, other consumers took the fast-food company to task on Twitter for caving in to the “food police,” hurting the company’s image on two fronts.

Hyundai

Ad Title: “Pipe Job”
Agency: Innocean Worldwide

Auto sales in Europe have been on life support since 2009, but that’s still no excuse for Hyundai’s suicide-themed commercial for the ix35 compact SUV. The unsettling ad, aimed at the UK audience, depicts a man attempting to commit suicide by running his ix35 in a closed garage.

The upside (and apparent selling point of the vehicle) is that the man’s attempt fails — because the new ix35 produces “100% water emissions” and is therefore harmless. A public outcry — including heart-rending blog posts from individuals who lost a family member to suicide — forced Hyundai to pull the ad.

Hyundai apologized and sought to distance itself from the commercial by putting the blame on Innocean Worldwide — although critics quickly pointed out that the agency is owned by Hyundai’s parent company.

JCPenney

Ad Title: “Back to School Shopping”
Agency: Young & Rubicam

JCPenney (JCP) has had so many troubles over the past couple of years that the list is too long to mention them all — the hiring (and subsequent firing) of CEO and Apple (AAPL) veteran Ron Johnson to plummeting revenue, earnings and stock price are only a small selection. So it comes as no surprise that the retailer has been equally snake-bit in its ad strategy.

One of JCP’s missteps this summer was its “Back to School Shopping” ad, which marketers believed would position the 111-year-old retailer as trendy and fashionable. Unfortunately for JCPenney, the ad outraged many parents, who believed it promoted bullying.

Outraged moms and dads took to Facebook, calling on the retailer to pull the ad. One parent said the commercial suggested that if kids couldn’t buy JCPenney’s clothes “they don’t deserve friends.” JCP did pull the commercial and wound up posting anti-bullying messages on Facebook and Twitter, but this was one more distraction the troubled retailer didn’t need.

As of this writing, Susan J. Aluise did not hold a position in any of the aforementioned securities.