Melodies can be good depending on the context. You can have a simple melody, and if the harmony behind it is interesting, it can make a very simple melody really different. You can also have a complex melody. The more complex it is, the harder it is to sing, and then sometimes it can sound contrived. You could write a melody that would be fine on a saxophone but if you give it to a singer, it can sound raunchy.
It takes time because the habitual response to that is very deep. It goes back to our earliest responses as babies. You have to feel safe, and if a sound is threatening, you're going to be upset. There are those early responses, depending on how and what kind of experiences you had.
Life is hard, and children have to be told how hard life can be…So they will be sympathetic to others. So they will understand that some people have it harder than they do and that a trip through this world can be a wildly different experience, depending on what chemicals are raging through one’s mind.