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

Directional fuses in an alternating current circuit.

Update:
the added benefit of a third usb Schumann Generator (S.G.) modified  for 13 bucks surprisingly is evident after a few notes...I cannot wait for my fourth and last (a bigger one power supply included 23 bucks) I modify all with proper stones and crystals to clean the source power and use some antenna  with a great success...

danvignau
Directional fuses in an alternating current circuit.

>>>>>Software emergency! Data Buffer overload limit exceeded! Learning function routine disabled.

Schumann Generator update:

Well I dont think that the S.G. is ridiculous useless pricey tweaks... It is my fourth one, cheap chineese one with an atrocious power supply that is garbage, then I put a cheap one but better and the improvement is across the board...This fourth one is the cherry on the cake...I am happy that I bought these little marvels, and if you want an upgrade this is one... Total cost 70 bucks for the 4 S.G. and the effect in the listening room cannot be overestimated at all...

The most ridiculous and useless tweaks I know of today it seems  are only those I dont experiment with in the first place...The problems of the tweaks are the companies that often sell them a price that are way too much...Experiment yourself and dont read reviews anymore...