Yes, the attitude of parents, especially critical remarks can have a devastating effect on children. It can injure self-esteem greatly which may lead to a negative role playing, almost like a self-fulfilling prophesy. Others however take the path of the rebel who carves out his own path.
Nevertheless what is done is done. One cannot turn the clock backwards. Besides it is all done in a state of ignorant goodwill believing that criticism helps improve whereas it is just the reverse. It is by showing and encouraging the beautiful positive side of people that life blossoms beautifully.
The key to self-esteem therefore lies in discovering your unique strengths and working towards realising your unique potentials and possibilities. Fighting to remove negative tendencies often makes it worse. It saps a lot of energies that should instead be put in cultivating the beautiful positive side. Each one is endowed with something unique, often like an undeveloped bud. In trying to become someone else we forget who we are meant to be. To draw an example from Nature, there is a destiny unique to a stone and another for a mountain. The stone lying idly has the potential to be sculpted into a beautiful idol or turned into a radiant step for people to go further. A mountain can do neither. Its destiny however is to inspire, to support several forms of life, and to challenge human strength. So too the Rose has its unique destiny of being appreciated and used as a symbol of love. But the grass is an indispensable presence in every garden and not only supports other forms of life but even in its death nurtures and nourishes and is useful in many ways.
Therefore each one must discover his own selfhood, the unique individual self through which Nature, God or Destiny seek to express. The more you do it the less you will compare yourself with anyone because each of us is unique and irreplaceable.
Positive affirmations and outlook is alright but more important is to discover your unique positive elements and express them in whatever way that comes naturally and for which Nature has prepared you.
Affectionately,
Alok Da