If there were no mean people in this society, no one to say hard words or vicious curses, and even unfriendly people disappeared, but at the same time there was a lack of good things, would I still feel that the whole world was full of goodness, just like that little boy did more than ten years ago?
Hello, my friend! To be honest, this question is not really easy to answer, or no one can give a standard answer at all, because none of us have experienced a perfect world, and more or less experienced things that are not as good as we would like them to be.
Humans have an innate desire for a better world, as symbolized by the biblical Garden of Eden, for example. Theoretically or imaginatively, if one hasn't experienced imperfection, one would probably look at everything as perfect, as you say. I'm not sure what point in time you're referring to, but the paradoxes of beauty and ugliness, good and bad, good and evil in the world are all relative, and perhaps before that point you rarely notice or experience imperfection often enough to ignore it. And when you encounter it afterward, the frustration and impact may be increasing and the hurt deepening.
The mood you're in right now, going forward, may have something to do with those vicious attacks in the past that still hurt you today. But on the flip side, not everyone who goes through the same thing becomes like this, because everyone grows up with different resources, and that's what creates the unique you.
Buddhists refer to inverted dreams and true reality as the two extreme states of human beings, and we all actually live on the spectrum between the two, to varying degrees.
I wish you all the best.