Why are people suffering?

Answer: They don't realize that life is a zero-sum game. For every upside there is a downside.

For instance desire and fear are opposite sides of the same coin. You don't have a desire without an accompanying fear. That I fear sickness means that I desire health. I want to live and I fear death.

That I want the cessation of fear and desire means I want to be free of these two forces that cause me to suffer. This longing to be free of the upside and downside of life is natural as it is born out of the fact that deep within myself I am free of incompleteness.

As a matter of fact we are born ignorant of our wholeness and this is painful so I want to get knowledge. So Vedanta gives hard and fast knowledge of our completeness/wholeness and existential suffering disappears. When suffering disappears, bliss appears. I can't be two things at once.

So am I incomplete and inadequate? Or am I whole and completely adequate to face whatever life has to offer? Am I a suffering entity or am I a blissful entity?

If you hear the teachings of Vedanta with faith you will realize that you are an unborn blissful entity. If you are unborn you can't die. You are immortal. This is what you can discover with the help of Vedanta.