I say it like this:
Imagine how much free time you would have if you stopped wasting time worrying about things you don't control.
Now imagine using all that new free time to become a good person.
Always keep your mind calm and composed, do not get too much excited of Happiness and get emotional in Bad Situations. Be focused only on facing problems and finding a way out of it.
#1 Live in Agreement with Nature – The Stoic Goal of Life
#2 Live by Virtue – It Is the Highest of All Goods.
For More Info.
Stoic philosophy says that virtue (four cardinal virtues of self-control, courage, justice, and wisdom) is happiness, and it is our perceptions of things—rather than the things themselves—that cause most of our trouble.
Avoiding emotions, both in good times and bad ones.