Punishment is a response to behavior that inflicts physical or emotional pain on a child. This can include yelling, name calling, hitting, sarcasm, ignoring, or isolating for a long period of time.
But punishment doesn't work!
Because your (the parent's) behavior is the punishment, children may seek revenge or retalliation.
Because children learn behavior from their parents, they will learn to punish others when they don't like something.
Punishment can hurt the parent-child relationship. They may choose to avoid you.
Punishment may stop the behavior in question, but it doesn't teach the child what to do instead.
Children can become immune or desensitized to the punishment; parents find that they must increase the punishment for it to have the same effect.
Punishment affects the way children think about themselves; it can harm a child's self-esteem and confidence.