Life is suffering
Life includes pain, getting old, disease, and ultimately death.
We also endure psychological suffering like loneliness, frustration, fear, embarrassment, disappointment and anger.
This is an irrefutable fact that cannot be denied. It is realistic rather than pessimistic because pessimism is expecting things to be bad.
Pain in life is inevitable but suffering is not.
Pain is what the world does to you
suffering is what you do to yourself.
Pain is inevitable, suffering is optional.