Being a religious person means that you believe that there is a Superior Force, beyond our understanding, which created everything we know today. As well as everything else that we have yet to discover, learn about. This Higher Force can be called God, Yahweh or by many other names. A religious person also frequents a church or some other place of worship, as a sign of their belief in that Higher Force. Those who don’t believe in such force(s) are called Atheists.
Atheists say that there is no need for a Higher Force to create everything that there is, especially not the Universe. The universe has always existed, it didn’t need Anyone to create it- it’s as simple as that, because if the Universe was created by Someone, then where did the Creator come from, or who created Him?
Another proof that there is no God, in the eyes of many Atheists, no matter His name - is the suffering we see around us everyday. People, animals and plants alike suffer, especially because of pests and because of what some individuals do to others - for sure God in His mercy when he created us, didn’t create something like pain and illnesses, did he?
A religious person, especially a Christian, would reply that it is easier to harm someone than to do good. They’ll even say that G-d “tests” us and our love for Him. but...
However, it was our original transgression and then the following ones that pained G-d. He wanted us to see it's not OK to make others sad, break their trust, or make them suffer in any way. So I think we suffer because we got too estranged from God and His ways. Everything started with Adam and Eve not listening to Him, and giving into the snake. Yes, G-d is vengeful, jealous, but He also loves us tremendously because He incarnated Himself and let Himself be sacrificed by crucifixion for our sins.
Many people would hide behind their religion to justify their behaviour. That can’t be right: one needs to think for themselves and then decide if this or that is right or wrong to do, especially when they know what their religion teaches. However, he really shouldn’t need religion to tell us “this is (not) ok to do” because Adam and Eve bit into the fruit that revealed them “good and evil.” That alone should be enough.
A good person is usually defined by the way they treat those around them. Compassionate is another way to say “good person.” You may or may not believe in an All-Powerful Creator, but you CAN be more compassionate towards others, animals, and the nature in general.