Nothing makes me understand depth of the following more than when I see people wondering about others' joys and their own sufferings.

I have never seen a grumpy person satisfied with life, just as I have never seen a happy person grumpy with life. It is all about how you comprehend life, experience joys and sufferings.

We all experience our share of joys and sufferings. We all consequently infer our experiences and evolve. Evolve to be either wise or bitter. Wisdom and bitterness are alternate choices. We choose to be either wise or bitter with what we lived, live or will live.