At very small scales, many solids have the ability to sustain extremely large pressures before wearing off, i.e., up to a few GPa. Some materials, deposited on top of such hard solids, undergo chemical changes at these pressures, thereby changing their mechanical or electrical properties dramatically. In my talk, I will discuss how first-principle molecular dynamics can be used to analyze the mechanisms responsible for changes in the response functions of the deposited materials. Specific examples will be zinc phosphates (ZPs), in their function as anti-wear additives in commercial lubricants, and doped pnictogen solids (DPSs), when used in non-volatile electronic memory or in programmable switches. Molecular dynamics reveals when and why ZPs show "smart material" properties and anticipate the possibility for DPSs to be switched with nanoscale piezoelectronic actuators.