Seriously. Electronics. Some kind of an electronics assembly kit. I observed the beneficial effect using a sound effects generator chip which came with instructions from Radio Shack.
Anyway, to get to the point, a kit either works or it does not. And there is no other answer. (Paranoia only able to seize on 'bad parts'--a rarity.) It is a go, no-go phenomenon. So if it does not work it is your fault.
Of course, we experience this online when something goes wrong technically, but no such confidence in the privacy of the computer technical relationship. Although there too, when a dilemna is solved, it clears the air but only in that one instance. But with a electronics experiment there is much less to be paranoid about.