Sometimes

Sometimes I drink of a liquid
That tastes of copper,
And is warm to the touch.
It is red as the rose,
But of a deeper shade.
It tastes different
Depending on the source,
Yet is my most needed element
To live.

Now tell me,
What would you say
If I told you
I had taken this element from you,
Just not enough that it would
Kill you?
You probably wouldn’t believe it.
But say you were a good friend of mine,
And you sometimes drank of
This liquid too.
I bet you would believe me then.

Not that it would bother you,

Because you've done the same to me.