Google Calendar can create a reminder for important dates like birthdays. The pop up for the reminder will only change as Google sends updates that alter color and format. The message stays the same.
Not so for the people on which a birthday falls.
Youth tends to love a birthday. A present, hidden in a box and further secured by wrapping paper, is a magical thing for the young. For others, the expectation of friends tendering words of appreciation is the pull. Many who are not so young, but perhaps young at heart, like a birthday for the same reasons.
On our birthday, all the world (when world is defined as that portion that affects us) reaches out and acknowledges our contribution to other worlds. We are all world builders, each of us the center, but depending on the introvert/extrovert combination within us, we encroach to various degrees on others.
Birthdays have a beginning but no end. My birthday will be the same in a thousand years. The world I am building commenced and is commemorated by that day.
Funny that unlike birthdays, worlds do end.
What continues is the encroachments we made while building. For some, the birthday not only continues. It is remembered.