The design of playware based on the lessons learned from user-friendly robotics suggests a focus on a number of design criteria to help achieving playware systems that can and will be used according to the Playware ABC by anybody, anywhere, anytime. The design criteria are described in this paper, and they include: modularity, explicit immediate feedback, robustness, simplicity, one-click, design. Each criterion is described based on the lessons learned from user-friendly robotics. We exemplify the use of these design criteria with the development of the playware system, Moto Tiles. The Moto Tiles system is designed as a playful prevention and rehabilitation system for seniors, who are normally not exposed to such high technology systems. The paper discusses how the design criteria allowed for a successful design of a user-friendly system, which is now used daily by tens of thousands seniors all over the globe.