Deceptively Simple Demonstration

Every infomercial advertiser wants to show its product in action, working flawlessly to solve the problem it was designed for. But what do you do if your product doesn't really look all that good in use, or if the difference between your product and your competitor's isn't obvious to the naked eye? Worse, what do you do if your product isn't any better than the competition?

You could hire actors Too Incompetent to Operate a Blanket to highlight the supposed deficiencies of the competition, you could hire an actor to play the Insane Proprietor (or hire two actors to be Two Guys in a Garage), or you could use Before and After Pictures to showcase your All-Natural Snake Oil. Or...you could show your product doing something it was never intended to do - and doing it well.

The secret behind the Deceptively Simple Demonstration is that the supposedly "difficult" task shown in the commercial is far easier than it looks - and is usually much easier than the task the product is designed for. It's a lot easier to blend a mobile phone into powder than it is to puree half a pound of cooked chickpeas, for instance. The advertiser is hoping that the customer doesn't realize that the demonstration is actually easier than it looks, or that he'll be so impressed by the demonstration (and especially the "power" of the motor, something relatively unimportant in most cases) that he won't even notice that it has little to no bearing on the job the product is supposed to do.

This doesn't mean that the advertiser is lying to the viewers, though: the product really works as shown. It's just that nobody is ever, ever going to buy the product for that purpose.

If the use shown is outstandingly different from its intended use, it might be a Refuge in Audacity or even a Parody Commercial.

Advertising

 * The Ur Example might be the 1970s Ginsu knife commercial that showed someone using a Ginsu to cut through an aluminum can. Even comedians of the time wondered why.
 * Later Ginsu commercials showed the blade cutting through an orange juice can - a CARDBOARD orange juice can.
 * When making the commercials, the staff tried cutting anything they had on hand, and if it worked they'd put it in the ad. This included a radiator hose, which was actually installed on an employee's car when they tested it. It's a wonder they didn't go for battery cables and electrocute themselves.
 * The Miracle Blade 3 infomercial shows a guy wielding a knife like a sword to cut right through a pineapple that's hanging by a thread from the ceiling. It's supposed to make the user think the blade is as sharp as a sword (not that most swords are particularly sharp, but they're counting on you not to know that) - it must be to cut through that tough, spiny pineapple rind, right? But pineapples are actually quite easy to cut through, especially just below the crown.
 * Most people use a blender for two things: to blend liquids with ice, and to puree vegetables or fruit. In the "Will It Blend?" series, Blendtec's friendly nerd blends iPhones, laser pointers, video cameras, golf balls, and the like. But they all blend easily because they're relatively high-density solids that pulverize into powder when blended. Most food doesn't act like that. When Mark Bittman attempted to use a Blendtec to puree chickpeas in a New York Times video, the viscous mass of peas was too thick to circulate properly and a bubble of air formed around the blades - not surprisingly, because all blenders do the same damn thing. To process thicker, denser foods, a food processor is your best bet.
 * In fact, the Blendtec spins so absurdly fast even on the lowest settings that it's really best for blender drinks (a case where motor power does matter); anything thicker will form an air bubble almost instantly.
 * The original Oxiclean ads showed Billy Mays removing orange-brown dye from a large bowl of water. While it's undeniably impressive, very few people need to clear dye from water on a regular basis.
 * Vacuum commercials and demonstrations work on this principle. Yes, the suction in a Dyson or an Oreck is strong enough to suspend a bowling ball, but what does that mean for your home? Not much, it turns out: without a decent beater bar to dislodge the dirt from carpeting and high-quality, thick brushes to sweep the dirt off hard floors, a vacuum with strong suction is little better than a vacuum with no suction at all (and even worse in some instances - strong suction can actually damage some surfaces).
 * Not only that, but the pressure produced when the nozzle is completely blocked by a bowling ball does not necessarily have anything to do with the air flow rate when the nozzle is against a surface being vacuumed (which is what actually matters for cleaning).
 * There was an infomercial back in the 90s for an iron cover which apparently was supposed to prevent users from scorching their clothing because they were too stupid to set the iron's thermostat correctly. (It worked by insulating the face of the iron, which meant you were basically setting your iron to High and ironing on Low.) One of the demonstrations showed the presenter meticulously ironing a thick wool casual sweater. Certainly wool does iron beautifully with very little effort and looks wonderful on camera, but who in the history of humankind has ever ironed a thick wool casual sweater?
 * A related gimmick is, as an example, using a dirtier floor or a darker stain on a lighter shirt for your product, and only cleaning the middle. Because the contrast between cleaned and uncleaned is greater, the product seems more effective.
 * Every insurance company likes to point out that people who switch to their company save hundreds of dollars. Impressive, until you realize that people who won't save money don't switch and are excluded from the calculation. Also an example of lying using statistics.
 * Twenty or so years ago, Crest showed commercials where half an egg had been treated with their toothpaste, then the whole thing submerged in an acid solution. The treated side remained hard while the untreated shell became soft and malleable. What they didn't tell you is that virtually any fluoridated toothpaste would give you the same result.
 * This is why toothpaste is one of the go-to examples of a parity product: one in which all competing brands are equally effective and largely interchangeable. In order to sell different brands, marketers have to resort to inventive (if mildly unethical) tricks like the egg-in-acid wheeze.
 * Every commercial advertising a pillow will show someone testing it by dropping a bowling ball, dumbbell or other heavy weight on it to show how supportive it is, often with a nice fragile egg under it to make a big messy result. But, unless you're a Metalhead, you're not going to be slamming your head into the pillow at that high of a velocity.
 * American Standard markets toilets that are powerful enough to flush several golf balls without clogging. Unless you poo like an elephant, or radically overuse toilet paper, you don't need this much flushing power.
 * If you give your friends swirlies on a regular basis, then the added flushing power means greater drenching and a funnier result.
 * Slap Chop ads only feature Vince Offer cutting things that have already been cut into bite-sized chunks with a real knife, in an attempt to disguise the fact that the Slap Chop is useless on anything bigger than an egg.

Live-Action TV

 * Deadliest Warrior often makes use of these demonstrations for entertainment value when testing various weapons. Hand weapons are often swung at targets that are braced for impact so that the full force of the weapon is transfered to the target. Fragile targets are also used for weapons that don't supply very much force. This ensures that each weapon cleaves or pulverizes its target to impressive effect.

Theatre

 * Harry Houdini frequently used this. Tricks seem more impressive if the audience only thinks they're difficult, for example in escaping from being locked in a safe. Ask yourself: are safes designed to keep people in, or out?