The most psychologically damaging things you can say to a child include.
You are bad.'' ``I hate you.'' ``I never wanted you.'' ``You were a mistake.'' ``You came from a drunken night.
``I wish I never had you.'' ``You will never amount to anything.'' ``You are stupid.'' ``You are ugly.''
``Your sister/brother is better than you.''
Or any variation on the above. Words do HURT even though it's said that words can never hurt you.
In reality words can and DO hurt you.
You should also never say things to your kids such as.
``I don't believe in you.''
``You're such a disappointment.''
``Why can't you be more like your brother/sister?''
Never say anything negative about your spouse.
And you should never avoid talking to your kids.