What Makes 'the Yearly Occurrence of a Calendar-Date' Something to Celebrate?

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As near as I can figure, the only significance is that 'Earth's position with respect to The Sun is nearly-identical (human astronomers guess) to the position we were in when something important occurred.' For instance, 'The Earth was near "this position with respect to The Sun" when (Microsoft Bing Rewards' Dashboard tells me) the Beach Boys put out their "Pet Sounds"-album (with songs on it like "Sloop John B" & "Good Vibrations" & of-course "Pet Sounds").' But what difference does it make "what 'date' it happened on?" Isn't 'the day of the year' just an 'arbitrary re-occurrence' (since somebody figured out that it takes about 365 sunrise-&-sunset's for the sun's arc to move from summer solstice to winter solstice and back again, and 'people who controlled "The Press" decided to number those sunrise-&-sunset's, name them & -groups of them after gods-or-emperors, and make everyone agree on "what to call them"'). https://en.wikipedia.org/wiki/History_of_calendars#Modern_calendars