Close to "So it goes"

"Do not seek to have events happen as you want them to, but instead want them to happen as they do happen and your life will go well."-Handbook of Epictetus.
This piece of the handbook reminds me of an important aspect of Slaughter House Five. Throughout the novel, Billy recites over and over again his famous "So it goes" phrase, and we can see how he lives happily knowing what is going to happen in all his life. We could say he wants things to happen as they do happen, and therefore he lives a happy life. However it is different because Billy doesn't really want things to happen as they happen, he just thinks that he can't do anything to change them , so I guess his life is happy because he understands that all is just destiny. I agree with the handbook of Epictetus about getting the best out of life's events, but I disagree and have always disagreed with "So it goes", because I think that maybe life has destiny, but if you were able to go back in time you could still change stuff, and I think you should always change for the better. You can always change for the better since we are human and we won't ever be perfect.