We get changed due to lack of love, sharing and when feel alone & sad inside but they also learn how to find reasons of happiness then...thus the people who laugh more are able to tolerate pain better because they have learnt to compromise with the circumstances and dont want to feel hurt physically or emotionally avoiding arguments and begging for love. Such people believe that when they cannot change the circumstances then change themselves according to the circumstances and find different reasons to live and move on in life.
When u have been constantly bullied, ignored, humiliated, scorned and pushed to the edge of the cliff and somehow given a chance to reborn. All Hell break loose.
My theory on life is that life is beautiful. Life doesn't change. You have a day, and a night, and a month, and a year. We people change we can be miserable or we can be happy. It's what you make of your life.