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

I'll go the other direction....the best tweaks are a good glass of scotch, a poke of herbal essence and the wonderful cover of night.  System always sounds great under these conditions.

I see. You treat yourself. 🤗

Can we have a little bit of fun here, just as the original poster intended?
I very much liked the reversed carpet story! Why is this getting ridiculed???  If it's all about subtle influences, and all sorts of snake oil - why should the fibres of the carpet pointing in the reverse direction NOT have an influence? After all the exotic room treatment we have done? Hey - we are here in FREE Of CHARGE territory. Why not try ??? Some years ago my then little kids rearranged the Persian rug in front of the speakers, creating ridges and bumps to play with toy cars! Did it affect the sound? YOU BET. So, as long as it's FREE, any tweak is OK. Thanks to glow_worm for the inspiration.

I just realized nobody mentioned freezing things in the home freezer. What’s up with that? You guys are slipping. I will be standing by for someone to point out to me that temperatures in the home freezer aren’t low enough to do anything. 😬

Reading reading this thread it becomes clear why sellers offer so many of these useless but outrageously expensive products.