A day, a ritual, nicked from the pagans by the church to adopt pagan holy days as their own and honor loved ones no longer among us.
Stoics of Ancient Rome and Greece implored people to keep death in mind all the time as a means of deeply appreciating life.
You cannot have been born, and be alive, without death.
The Greek stoic Epictetus: Don't dread death, dread the fear of death.
Non omnis moriar.
Or, put another way, every exit ramp is the start of a new adventure.