Bitterness can create methodical WITCHES/WIZARDS out of someone who was once as harmless as a dove!  It is the core character of witches and wizards.  BITTERNESS will activate a mission to control the destiny of others.   Bitterness will ignite a relentless passion to destroy others without a cause.  It will make you do things you never dreamed you would do. 

BITTERNESS leads to sin!  Psalms 37:8 Put an end to your wrath and be no longer bitter; do not give way to angry feeling which is a cause of sin.

The only antidote is to forgive!  Agape!