There are two products that immediately spring to mind, and I apologize if they were mentioned before and I missed it while skimming through posts. Both of these were advertised on TV, and both of these were bought by gullible little me at our local Walmart.
The "Quick Chop", the "fast easy way to chop mince slice and dice with just a tap". I bought this out of curiosity and with no real expectations, and it's a good thing that I wasn't expecting much. It worked all right the first time, but it was a pain to clean and it marked up the cutting board. After that, the blades went dull, and there is no way to sharpen them.
"Smooth Away", a buffer for unwanted face/body hair. It worked, yes. It buffed away the hair...after being used long enough to make the skin red-raw. So, it didn't work very well, and it wasn't really worth it. Again, no expectations, just curiosity.
The "as seen on TV" aisle is a source of amusement these days.
"The "Pasta Boat"? Really? Yeah, I think I'll just stick with our good pot and a colander, thanks."