The word ‘placebo’ is derived from the Latin verb placere, meaning ‘to please’.
Hence, whatever pleases me is called a placebo. Assets, real or imagined, please me, hence are placebos. Liabilities displease me. Therefore are called nocebos.
The human brain, i.e. the Biological Navigation System (i.e. Bio-Nav), processes only neutrons, i.e. bare data. Like all other computing systems it does not distinguish externally accessed from internally created data. Its job is to create a virtual (probably) best next step to be taken by the body. Whether or not its calculations are right (meaning, leading to an increase in relative survival capacity) is confirmed by subsequent reality (i.e. actuality) testing, meaning contact, and which generates new data.
Any datum that serves to increase survival capacity is an asset. The increase is signalled with pleasure (or happiness). Hence, each and every asset functions as placebo. Each and every liability, i.e. which decreases relative survival capacity, functions as nocebo.
A bio-system maintains optimum survival capacity by acquiring as many placebos, real (i.e. external) or imagined (i.e. virtual), as possible.
The most common source of (imaginary) assets, hence placebos, is public or private entertainment; in short, the (mind-) games we play.
See: Enlightenment i.e. as verbal placebo