They no allow kidds to try new things, and like they will become shy.
They limit the ability to speak.
They limit the ability to understand life, as they limit the attempts of the kid to be independent.
They limit the thinking of the kid, as kid will see that there is only 1 way, parent's way.
In the end the child will be abusive in relationship as he wasn't understood by his parents, and the same he/she will do with partner and kid.