a color that’s definitely gray, but not very dark

They say it's all 
black and white.
Good or bad.
Right or wrong.
But sometimes it's a delicate shade of gray,
and it's evil, but then it gives your life just before it disappears,
and it's not correct, but it's not incorrect.
Who is it, then?
And what?
Why do we never cease to label things
the way we think they should be,
but then
they're not?