They don't know how to release their pent up anger, and so they channel it onto their children. Words and bitterness hurt some parents when they were children. They have learned to deal with others in the same way. The difficulties and frustrations in their lives affect the way they relate to their children. Some parents have serious problems with drinking or drugs.
Some parents direct their anger at their children.
They forget how bad a child is made to feel because of what parents are saying and doing. Improve your own life Stop. Think about what you are doing. Take time out. When you are angry and upset, give yourself time to calm down before you respond to your child.