This paper introduces UCX (User Charging Experience), a comprehensive theoretical framework for designing electric vehicle (EV) charging services. Building upon the paradigm shift that defines EVs as "mobile living spaces" rather than traditional vehicles, UCX proposes that charging time should be reconceptualized as "living time" rather than "waiting time." The framework integrates three dimensions—Journey, Channel, and Emotion—with four design pillars known as the SFSC Framework: Simple, Fast, Secure, and Care. A key innovation is the replacement of traditional "Call Center" support with "Smart Care"—a data-driven decision system that predicts and prevents issues before they occur.