Cat
Feline reliability operates on principles that would baffle any engineer. Cats perform assigned tasks, primarily rodent elimination, with intermittent excellence punctuated by extended periods of what appears to be deliberate non-cooperation. A cat may patrol the premises with lethal efficiency for weeks, then suddenly develop an inexplicable fascination with a wall for three consecutive days.
Performance metrics prove impossible to standardise. Some cats eliminate every mouse within a postcode radius whilst others form apparent non-aggression pacts with local wildlife. The variability extends to basic functions, with some cats reliably greeting their owners and others treating human presence as an unfortunate but tolerable inconvenience.
Light Bulb
Light bulbs deliver functionality with near-absolute consistency. Flip the switch, receive photons. The transaction requires no negotiation, no mood assessment, and no strategic placement of treats. A standard incandescent bulb provides approximately 1,000 hours of reliable illumination before failing, and even that failure occurs predictably, typically at the most inconvenient possible moment.
Modern LED variants extend this reliability to approximately 25,000 hours, representing a quarter-century of dependable service from a single unit. The light bulb asks nothing beyond electrical current and delivers everything promised, a transactional clarity cats find philosophically objectionable.