Chance was a big part of life really. It was all by chance that things happened the way they did, of who ended up in your dorm and house, who was picked to be what around you and where you ended up because someone else was next or behind you.

Really, Neville only had such a boring and inadequate life because Harry had been chosen and not her. What chance! That's all it was really, chance. Because their lives had began the same, only Harry was chosen instead of him, and for this reason, Neville lived a life without constant fear, without pain and without being harassed by the media or by those who resented him for his fame.
Would Draco hate Harry so much if Neville had been chosen by Voldemort instead? If it had been him chosen, would his parents still be practically gone to him or would researchers from everywhere actually try their hardest to get them well again, just because he was The Boy Who Lived?
Or...if he had been chosen, would he have even survived that fateful night?

The thing with chance though, was that you never knew how things would be otherwise and it could drive you made thinking about it. All chance was, was a flip of a coin so without that coin, what would have happened? What if someone hit it with magic, who knew how things would be like now?
Would he be the captain of the Quidditch team?
Would he have had a girlfriend by now?
Or did that talent belong to Harry alone, despite what had happened to him? How much of it was Harry's true self, and how much of it was what Voldemort had done when he had tried to kill him?

Chance was what mainly controlled their lives. Snape was Potions master because when he had first joined Hogwarts as a teacher, someone better had already been there as Defence Against the Dark Arts Professor. Life was hell sometimes in Hogwarts because Draco Malfoy had been born the same year as they were, and so he was in their year and their classes. Ginny wasn't his friend any longer because she had been asked out, and Hermione had been trapped by that troll and saved by Ron and Harry and that's why she had stopped hanging out with him just weeks after they had started school there.

Without chance, if everything was controlled properly and everything happened for a reason, would things be more just in the world? Would he, Neville, have parents or would he still be without? Would his grandmother be more loving of him, or did he deserve all that?
Would he still be a coward, without friends, and a disgrace to the family? Was that from chance, or was that from him?

Who knew? It was hard to tell with chance, and there was nothing to do but live through it, and someday learn to control it.
Chance was fickle.