Of the 10 plagues, Pharaoh hardened his own heart for the 1st 5 plagues, and HaShem hardened Pharaoh's heart for the later 5. IMO, while there are numerous reasons why HaShem did this, I think among them was a punishment directly to Pharaoh. Pharaoh chose with his free will to be evil 5 times in a row, and then would have thrown in the towel on the 6th plague but HaShem punished Pharaoh's abuse of free will by taking it away and forcing him to dig the hole deeper for himself to the point where he would eventually lose everything. -- If we choose to be evil over and over and abuse free will, God can take away your free will and you will continue to "choose" being evil as if you are captive, until hopefully God grants you return of your free will again.
Someone like Norman Finkelstein comes to mind. A man who has chosen to do evil, committing murderous Lashon hara against a people [his own brothers and sisters as it would be] he knows do not deserve it, so often that he, seemingly, is isolated from Teshuvah [It would truly be an act of God to see this man become righteous in our days]. When looking at a man like this one can safely predict his actions and words w/o being surprised. He is so predictable and so entrenched in his ways one must wonder if he really has the power to choose his evil actions at this point in his life or if he does evil because he has forgotten what it is like to be anything but what he is now [he is blind to righteous action because it has become unknown to him; he has braided evil to his core so that righteousness is not something which exists in his mind]. Finkelrat still serves a purpose by existing as an example of what not to be, and perhaps he mechanically serves as a cog in God's plan for the world at large to turn against the Jews before our final redemption [there is nothing like a Judenrat to rev up anti-Semites "justification" for their hate].
All I know is one really needs to not abuse their free will. If free will is not exercised readily, and healthily it can atrophy and become unusable.