The quality of design determines the performance of all tribological systems. Tribological failures of the system may be avoided through rational and creative design. In that sense, there is a symbiotic relationship between tribology and design. Many tribology problems encountered are often the result of poor system design. By properly designing the tribological system, potential failures caused by friction and wear can be avoided or minimized. Continuous testing of poorly designed tribological systems, which occur in some cases, can be costly without noticeable improvements in the system performance. Since well-designed products yield immense benefits, the creation of tribological systems based on rational design should be pursued. The biggest source of tribological problems is the coupling of the functional requirements (FRs) that are introduced during the early stage of design. We should attempt to eliminate coupled tribological systems to improve the performance of tribological systems. Some examples are given to illustrate the importance of rational designs in implementing tribological systems, including the design of additive manufacturing systems.