A comparison between Romeo and Juliet and Lord of the Flies is that both show the dark side of human nature.
Although at first glance the two plots seem to have little in common, there is one striking similarity. In the feud between the Montagues and the Capulets and the violence of the boys on the island, we see the worst of what humans can do to each other. Both are examples of senseless violence. There is no reason for it, yet it continues. It is just human nature, apparently.
When Romeo sees the aftermath of the brawl in Act 1, he comments on the nature of violence in his town.
O me! What fray was here?
Yet tell me not, for I have heard it all.
Here's much to do with hate, but more with love.
Why then, O brawling love! O loving hate!
O any thing, of nothing first create!(Act 1, Scene 1)
Romeo is aware that people are killing each other in the streets for no reason. The two families and their affiliates hate each other for no reason. They would just as soon kill each other as look at each other.
In Lord of the Flies, Simon is also aware that the “beast” the boys are afraid of is really the dark side of human nature within themselves. He comes to this understand when he communes with the pig’s head.
“Fancy thinking the Beast was something you could hunt and kill!” said the head. (ch 8)
Ironically, both Simon and Romeo are killed because of the thing they recognize as the dark side of human nature. Simon is attacked by the tribe, who think he is a beast. Romeo kills himself after he kills Tybalt in a duel and is banished.