Cat
The domestic cat demonstrates a lifespan of 12 to 18 years under typical indoor conditions, with some individuals exceeding two decades. This longevity permits the development of genuine relationships, accumulated shared experiences, and the formation of mutual understanding between cat and human. The cat's extended presence in one's life allows for personality appreciation that deepens over time.
Cats also maintain their essential nature throughout their lifespan. An elderly cat remains recognisably feline, with the same species-typical behaviours that characterised its youth, merely executed at reduced velocity.
Individual emails possess effectively zero longevity as relevant entities. The typical email remains pertinent for hours to days before obsolescence renders it archaeological. The email system itself has demonstrated reasonable longevity, operating since 1971, but the messages it conveys are ephemeral by design. No email has ever been mourned upon its deletion.
This transience creates a peculiar dynamic wherein enormous cognitive resources are expended upon communications that will matter to no one within the fortnight. The email demanding immediate response today will, in all probability, be entirely forgotten by next quarter.