Tea
Tea's reliability approaches mathematical certainty. Assuming proper storage conditions and competent preparation, tea performs identically every time. The Camellia sinensis plant has provided consistent results for over 5,000 years without notable failure. Tea does not experience moral dilemmas, romantic complications, or vulnerability to green crystalline minerals. It does not occasionally turn evil due to red Kryptonite exposure. Tea's failure rate approaches zero when basic preparation protocols are observed.
Superman
Superman, despite his considerable powers, presents documented reliability concerns. Kryptonite exposure renders him entirely non-functional. Magic bypasses his defences entirely. Psychological manipulation has repeatedly compromised his judgement. The Death of Superman storyline demonstrated his ultimate vulnerability to sufficient physical force. Additionally, Superman has experienced multiple timeline alterations, suggesting inconsistent continuity of service. For entities requiring dependable intervention, these variables introduce unacceptable risk profiles.