"
Life is pain
Suffering is optional"
...is just
part of the life equation and is helpful at times. We will always have difficult and painful times. We will always face challenges and unfairness. How we choose to see things is like a lens that can alter the reality, be it positive or negative. The "lens" is also known as our attitude.

I see "attitude" as the stuff we carry around with us. What we show up in the room with.
I guess we can also throw in the old saying,
"Life is 10% what happens to you and 90% how you react to it."