There will always be choices in life we have to make. And it's not always clear where one will lead and what would happen if we had chosen the other - And maybe because we can never know, we don't need to. But if we keep believing in the choices we make and bettering our own lives and those around us, we've chosen the best path possible.
If we always long for greener grass, we'd just be standing still at a fence. Basically Wilson from Home Improvement (without all the wisdom).