Oddities of life

Some people say that everything in the word is in balance somehow (or at least should be..)
So to feel happiness and joy there serves the right amount of contrast in terms of desperation or worry... also that sweetness and bitterness (or sourness??) are both needed to make life bearable does not sound too controversial.
But why does it seem that some people are fighting for their life and might not succeed whilst others just throw away theirs without any need and destroying the world for so many people that cared about them?
I cant help finding this one of the very horrible things but I have no idea of what to do about it. If you suppose that everything that happens has a meaning and some sense, then my mind is surely too small to find it.