"We can’t wrap our collective minds around the concept of nonexistence." Well said, Diane.
I think humans can't imagine true nothingness. What we picture in our heads is darkness, but there is still the conscious self that perceives it. There is no sense of self in oblivion if that is what awaits us in death.
I suppose that is what makes the idea of death uncomfortable. True nothingness is something we can never understand because it is incompatible with existence.