Coffee
Coffee's reliability stems from its predictable biochemical interaction with human neurology. Caffeine's half-life of approximately 5-6 hours provides consistent, measurable effects. The substance performs identically whether consumed in Tokyo or Toronto, during crises or calm. Its mechanism requires no motivation, mood, or moral judgement from the coffee itself.
Quality variations exist, certainly, but even the most regrettable instant coffee delivers its adenosine-blocking properties with mathematical precision. Coffee has never failed to appear because it was distracted by events in another city or trapped in a parallel dimension.
Superman
Superman's reliability suffers from what analysts term protagonist availability syndrome. His assistance depends upon his awareness of a situation, his physical proximity, and the absence of competing crises. Historical documentation reveals numerous instances where Superman was unavailable due to time travel, space missions, temporary death, or romantic subplot complications.
Additionally, his effectiveness drops to zero in the presence of Kryptonite, a mineral whose distribution across Earth remains concerningly unmapped. One cannot schedule around his vulnerabilities.
VERDICT
Coffee prevails through sheer consistency. It has never been incapacitated by glowing green rocks or required resurrection. It simply works, every single time.