when will all these pains end?

it is really painful to see people who are suppose to be brothers or sisters or even lovers sadly in pains due to envy. I find it difficult to belief why some families are always happy and others are always sad. but the bittom line of all the problems is lack of understanding of what Allah the Almighty does. He does what He like and we as people can not do any thing about that, just given thank to Him in any case and remember that He know it well.