Happiness is determined by feelings which are the body’s internal response to external situations. You feel sad if you are used to feeling sad in a given situation even if there is no need of feeling sad given the change in context over life.
For example, if a child is slapped by an adult, he would feel sad as he is hurt and too small to respond. But, if an adult is slapped by another adult, the adult does not need to feel hurt/suppressed by physical abuse. The automatic internal response of feeling suppressed by a slap or verbal abuse can be redirected to a more self-empowering, rational response with awareness.
For example, with self-confidence, the adult can walk away in anger by assuming that the abuser is a devolved soul or ignore the abuser as a negative, irrelevant entity or slap back to revert back energy exchange or give advice on being peaceful or meditate in a positive vibration when alone, to transmute the negative energy received into positive.Feeling small is not required as a response in adulthood but it is an automatically created response by the subconscious mind which is not trained in meditation.
Meditation neutralizes negative energy inside you such that your own frequency rises and you mentally move away from people who make you sad by choosing detachment.
Schools need to be careful as education needs to train children into positive thinking.
For further reading, please refer to the book - A COURSE IN EMOTIONAL ENERGY MANAGEMENT, a soul's perspective .