Monday
Monday operates with a mathematical certainty that would make Swiss watchmakers weep with professional envy. Every seven days, without fail, this temporal phenomenon manifests itself upon an unsuspecting populace. One can set calendars by it—indeed, one must, for Monday permits no negotiation. The circaseptan rhythm of human existence ensures that Monday's arrival can be calculated centuries in advance. Ancient astronomers could predict Monday's coming with the same accuracy as solar eclipses. This absolute predictability, rather than providing comfort, merely extends the period of anticipatory dread. Office workers report symptoms of 'Sunday Scaries' beginning as early as Saturday evening, demonstrating Monday's remarkable ability to project its influence backwards through time itself.
Earthquake
Despite humanity's considerable investment in seismological research, earthquakes retain their status as nature's ultimate ambush predators. The Earth's crust guards its secrets jealously, offering only probabilistic whispers about potential tremors. Scientists speak of 'seismic gaps' and 'recurrence intervals' with the confidence of fortune tellers reading particularly muddy tea leaves. The Parkfield Earthquake Experiment, designed to catch a predicted earthquake in the act, famously demonstrated that even the most instrumented fault line refuses to perform on schedule. This unpredictability, whilst terrifying, does grant humanity something Monday categorically denies: the blessed possibility that tomorrow might not bring disaster. An earthquake might strike in ten seconds or ten centuries. Monday, however, is always precisely one week away from the previous Monday.