kamma that has been done gives result exact to its cause. When there is cause. there is effect. Person who does the kamma will definitely receive its outcome.
When the person is happy . whe ther he or she is that Person it can be realized that good deed will give effect.
That person is enjoying the effects of its cause.
The ordinare person may not realize this.
But is should be understood that the good cause of happiness is the outcome good effect . Good result dose not arise form bad cause
When an individual is suffering misery whether it may be ourselt or other person it is definite that unwholesome cause produess bad effects
Thougt an ordinary person may not realize this , be or she should understand that cause of suffering is due to unwhole some action. Unwholesome effects are due to bad cause , never form good ones.