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

My vote: Furutech Outlet Cover 105 NCF $220, with “special crystalline material that has two “active” properties.” https://www.thecableco.com/outlet-cover-105-ncf.html

" You ever try and ask your power company to correct the direction of the wires connecting your house to the local transformer?"

Yes, the restraining order is still in effect I believe....

" 'You ever try and ask your power company to correct the direction of the wires connecting your house to the local transformer?'

Yes, the restraining order is still in effect I believe...."

Thanks for that!

A great example of what can happen when a self appointed expert offers an appeal to the imagination entirely devoid of method, experiment and most importantly, evidence. 

The result? A true laugh out loud moment.

Audiophilia doesn't get much funnier than this.. 
This is a Hobson's choice. How is one to know without either resorting to pure speculation or admitting that you were a rube who paid a boatload for fairy dust? You can't win either way. I prefer the former so I nominate based on common sense and my own sense of reality;
1) anything from Perfect Path Technologies
2) this; https://www.musicdirect.com/equipment/furutech-demag-lp-demagnetizer
But at the end of the day, isn't any power cable priced above maybe a thousand bucks and isn't any interconnect above maybe $2,000 and any speaker cable above say $3000 a tweak-a ridiculously expensive tweak? What about $5,000 PC's and 10K speaker cables? Expensive wire to me is a tweak. The highest priced wires are the highest priced tweaks. I think wire makes a difference. A lot of tweaks make differences. 
I have another one for you-crazy fancy casework and faceplates to amps, preamps, phono stages, any exotic piece of equipment. Take D'agostino gear encased in jewel-like outer-clad. It's F-you bling bling. It's a tweak because you can look at it and believe that it sounds better based on how it looks. Any honest manufacturer will tell you that fancy casework adds more the final price of the product than any other aspect of the piece. Pro-ject, iFi, and at one time Musical Fidelity realized this and captured a market eschewing the bling-bling. Steve McCormack has always stayed away from fancy casework. Oh well, I digress. 
fsonicsmith sez ...

"1) anything from Perfect Path Technologies"

I guess at this point we can assume then, that you have contacted PPT and accepted their offer for a 90 day, money-back, no obligation trial on their products, have given them a fair trial, and then found them to be unacceptable to you, correct? So, please enlighten us ... which products did you try that you found to be ineffective in your system?

I’ll wait.

Thanks ...

If you look at the first comment to the OP, it makes the very same point as yours. So here we are, 144 comments later, back to where we started.
Full circle, full stop.