First of All i wanna suggest you to wear cap because weather is hot and sunlight is attacking on you bald head like mine. Just kidding.
Ok so my answer for your question is simple & short.
People are good or bad with their behavior & their behavior is pre-set in their mind by God. So they will act as they are programmed by God . Also we will do the same.
Other side some religions are strongly showing their majority. For Example i met two person. one is belongs to my religion & another is my opposite . My Internal feeling will be more for my religion instead of other . This is only just example . Not to hurt any religion. But its also an effect to show good or bad .
Situation also impact about good or bad. For example. If i met some one & same time he is upset with someone . it is possible that he will treat me not good.
& last is simple Do good have good.
Thank you