The Westminster Shorter Catechism’s first question and answer is: “What is the chief end of man? Man’s chief end is to glorify God, and to enjoy him forever.”
This chief end (or purpose of man) does not start when we die. For every Christian it ought to start now.
Instead of glorifying and enjoying God, the chief end of many Christians is to enjoy the perverted entertainment and life-style that this Satan-controlled world system offers, and then when they die enjoy God forever. Such a life is a contradiction and does not glorify God.