Every material in the universe is constrained by pressure, ranging from nearly zero in the vacuum of interstellar space, through 1 atm at sea level on earth, to unimaginably extreme pressures of 40 million atm in the core of Jupiter or 10^29 atm in the core of a neutron star. As a fundamental thermodynamic variable, pressure governs the physical properties of condensed matter by changing the interatomic distance and thereby controlling every aspect of the interaction of electromagnetic forces within a system. Therefore, the study of pressure effects provides fundamental insights into the factors that control materials properties and can even guide us to design and synthesize innovative materials that are applicable at ambient conditions. In this talk, I will address some of the most exciting examples of pressure effects in magnetic materials, superconducting materials, and potential hydrogen storage materials from a general perspective, while highlighting the unique challenges of various high-pressure techniques. I will present a hopeful picture that underscores the singular power of applied pressure to provide a pathway to innovative functional materials.