Coffee
Coffee's reliability approaches the mechanical. Given standardised inputs (water temperature 90-96 degrees Celsius, appropriate grind size, quality beans), outcomes remain predictable within narrow tolerances. A competently prepared espresso in Tokyo will deliver substantially similar effects to one made in Toronto. This consistency has enabled global franchise standardisation, ensuring travellers can obtain familiar stimulation regardless of longitude.
Failure modes exist but remain manageable: stale beans, improper extraction, excessive milk. None threaten existential consequences. Coffee will not suddenly decide to visit Tom Bombadil instead of assisting with one's morning presentation. Its dependability forms the foundation of modern productivity.
Gandalf
Gandalf's reliability presents considerable variance. His habit of departing at critical junctures leaves those depending upon him in precarious positions. The Fellowship's journey through Moria ended with Gandalf's apparent death, a catastrophic reliability failure that nearly doomed the entire mission. While he eventually returned, the intervening period of gandalf-absence created substantial operational difficulties.
Furthermore, Gandalf's priorities may not align with the user's. He concerns himself with the fate of Middle-earth, not with whether one successfully completes quarterly reports. His divine mandate supersedes mundane scheduling requirements, rendering him fundamentally unsuitable for tasks requiring punctual, consistent support.