If a toddler leaves her favourite book outdoors, it will get wet and damaged. She will have to wash them herself. Parents want children to be socially acceptable and to be good friends to others. For this reason they teach pre-schoolers to share toys and to take turns. Parents expect children to be polite.
Children are more likely to behave positively if that is a family expectation.
Children need guidelines for their behaviour. If a parent's expectations are too high, a child will constantly feel as if she is failing. By encouraging her to meet achievable expectations, a parent will help her develop a sense of self worth. Parents want to maintain some order in their lives. Consistent, loving discipline at home gives a parent the best chance of helping his child to be healthy, happy and well-adjusted.