What is it about death that you fear?

Some people simply fear death. I do not really understand that. Death is inevitable, so that is that.
But some people fear the manner of death.

Nobody wants to die slowly, wasting away because of some degenerative or debilitating disease. That is understandable.

And when I was in the service, although we all accepted the possibility of death, some people (me included) worried about dying “badly” i.e. screaming in pain or panic.

So what is it about death that you fear?

Is it death itself?
Or the manner of death?