Well while I can agree that ultimately we are all responsible for our own happiness....
I don't agree that things do not happen for a reason... even when it's something not so great.
Some people that come into our lives are FOREVER... I've got 2 little people that are proof of that in mine
It is in making choices of what direction to take when things go wrong or you find yourself unhappy that makes all the difference... as we cannot change or control others, but we CAN change and control ourselves.
My two cent's