This is a question I’ve asked myself many times, especially when thinking about my sister’s life.

She faced not just one, but three different cancers. She had to transform everything—her body, her lifestyle, even her blood type changed. She lived in different places depending on where she was receiving treatment, often separated from her children, not knowing when she’d be able to hold them again.

And yet, she was happy.

Not because her life was easy—in fact, it was deeply painful—but because she chose to be happy.

She was grateful for every sunrise, every chance to breathe, every moment with the people she loved.

She didn’t see herself as a victim; she was the protagonist of her story.

She didn’t let complaints take up the space that gratitude could fill.

Happiness doesn’t always depend on circumstances. It often depends on our attitude toward them.

Complaining reinforces everything negative in our lives; gratitude opens space to see what is working, what we do have, what is still possible.

As Viktor Frankl, psychiatrist and Holocaust survivor, wrote:

“Everything can be taken from a man but one thing: the last of the human freedoms—to choose one’s attitude in any given set of circumstances.”

We can’t control everything that happens to us, but we can decide who we will be in the face of what happens.

Happiness, to a large extent, is that choice.