However, there are so many other things which we shall never manage to completely master. For example, other people -- no one will ever be able to fully control another person. We can't change other people's thoughts, feelings, or actions, no matter how hard we try or how much we may wish to do so. Nor can we change the weather. Or stop time. Or become invisible. Or sprout wings and fly. You get the idea! :)
Instead of obsessing over things that we will never be able to control, it may help to simply control our own selves. We can change the ways which we think, which will in turn change our fears, our appreciation for all that life has to offer, views on our own selves, and the people which surround us. When we change our own inner workings, our environments will also change in response to those things.
Remember: the next time you feel as if life is out of control and there is little that you can do, just take a step back and go with it. See where life takes you. Choose your battles wisely, and you'll be a heck of a lot happier.