When one does bad things it shows that one is bad.
 

What do you mean by 'shows', di?
 

That shows that men are born sinners; we have the original sin inherited from the first Adam.

But the fact there is some good in this world, shows that there is common grace. Common grace prevents men from becoming even worse. Men are totally depraved, but not utterly depraved. And remember that men are created in the image of God.
 

Another way to put it is that man's depravity is total in extent, but not in degree.