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

This thread has turned in an unexpected direction.
Tweakers unite!

My system, even if the sound is wonderful now, is very low cost audio system, then almost all tweaks are for me overpriced...They are ridiculous only after I have try them or replicate them if their use is revealed not useful...They are overpriced tweaks that are very useful, resonators for example, it is simple to replicate them at low cost...

Side note: there are many materials, I oft pick on Sorbothane not unfairly, but others,too, that are either sold as viscoelastic material or marketed as audiophile material that actually do more harm than good, even if there is some constrained layer damping going on there can be some energy storage going on too. The objective is to interfere as little as possible with the rapid exit of vibrations from the system whilst disallowing vibration to enter the system from the floor. I’ve oft talked about the necessity for a comprehensive plan of both vibration isolation AND resonance control. Many of these so called viscoelastic materials over do things, and even though you might admire your handiwork, you’ve committed yourself to a life of over damped sound. It’s what Acoustic Revive calls in their badly translated marketing literature, over-dumping.  

You are right Geoffkait , isolation and resonance control are 2 things and different things to clean and control... In my case the sorbothane duro 70 (other duro are problematic for me) is glued near the drivers speakers and under the feet and it seems to control resonance with success...The 2 granite plates + bamboo+cork+quartz seems to isolate relatively well my gear...It is not perfect but the difference are so great that I stuck with that...Cost is King in my sonic country...

I slightly disagree regarding over-damping. A chassis can not be over-damped, it can only be under-damped. If you apply the wrong damping material, it can be under-damped at certain frequencies and amplitudes. That can be worse than no damping. If you apply the correct type of damping that uniformly and consistently eliminates all chassis resonance and vibration at all frequencies and amplitudes, then you have total damping, which is what you want. Why on earth would you want the chassis to be vibrating at all? Even worse, to be vibrating only at selected frequencies?

Converting vibrational energy to current and then heat in situ is a more instantaneous and effective method of dealing with the problem of vibration, than any isolation method. As long as all frequencies and amplitudes are dealt with consistently.

Unwanted vibrations will bounce and reflect throughout a component chassis many times before exiting via the earth or the atmosphere. You don’t want that. Kill ’em fast. Convert them to heat on their first pass.