What’s your vote for the most ridiculous, overpriced, and useless tweak?

I humbly add Feng Shui and Orgone. 

What about my vote for the Maxiimus P16?

ridiculous - a glowing crystal pyramid powered by two "tachyon accumulators" housed in a tin box.
overpriced - 1800 Euros
useless - it generally makes the sound worse, smears focus and destroys the soundstage.

What’s more, they promise a "flow of electrons" from nature and electrons don’t even flow.

http://www.kempelektroniks.nl/en/918/kemp-elektroniks/products/shunt-conditioners/fostac-maxiimus-p1...

On the other hand I like their WA Quantum Chips. 

I propose to separate the 2 matters : the more ridiculous tweak and the more overpriced... The more useless and the more ridiculous tough may overlapped sometimes, but the more ridiculous(like salt lamp) is not always the more useless … And for me with my low priced vintage audio system almost all tweaks are overpriced, then it is necessary to replicate without buying when I can...

As much as I distain disagreement the salt lamp doesn't do anything to the sound IMO. I had someone measure the number of negative ions produced by the salt lamp and the number is zero. Now, I'm not saying salt isn't a pyroelectric material, but the bulb in the salt lamp doesn't generate sufficient heat to produce negative ions. even tripling the wattage of the bulb still does not produce any ions. But the lamps are pretty, I'll grant you that.