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

In the link above, as removed from pertinence about audio reproduction as it is, there are two moments that emphasize limits of isolation.

At around 2:45, word "relatively" and at around 6:45 "bonding them" ("connecting them", one could say).

In fact, there is much more later in the video, but those two are enough for aspiring novices.