Socially, your birthday celebration is akin to your funeral; a
time to bring people together around you to celebrate your life,
with the main difference between that most people don't lie down
during their birthday celebrations, at least until after the
cake.
The cake at funerals is served later. You don't get a piece.
When you go through a sensation of "life passing by" during a
birthday, which can happen at any point in one's personal
timestream, you are the only one crying at your birthday. At
your funeral, you do not cry. Another difference between
funerals and birthdays.
Perhaps if our death-date was known in advance, we would have
"Happy future death-day" celebrations each year, as a sort of
countdown rather than a count-up. In that case, you'd at least
get to eat the cake.
