As a child, there are many things in life we dont understand. Sometimes, we see good and bad examples of how we should do things. Our parents should always teach us to do things in the right way.
We should try not to let our feelings overtake us. Sometimes, its easier to do the wrong thing. And this is just what Cain did. He did not give his best, and because of that, his gift was not accepted.
But his brothers gift was accepted. He became jealous and hateful, and he hurt his brother. He did the wrong thing. We need to try to love and care for one another, even when we dont feel like it. Remember, it is always better to choose the right way.