It is quite upsetting if you believe that your existance is meaningless and insignificant. The world can be a very cold place if you find purpose only through yourself. Why are we here? What is my purpose here? Why do I exist? If our existance is the result of pure randomness, what a disappointing thought it is to know that all our accomplishments are meaningless.
I am a photojournalist. I exist to change lives through pictures. I can singlehandidly raise awareness on important topics, bring to light a person or group of people with a specific issue or importance to them, or simply make someone smile everyday. I can make people stop and think about what is going on in the world, why there is famine, disease, crime, or poverty. I can show a rich man the living conditions of the poor, induce that rich man to make a contribution, and therefore make a difference.
I dont belive in afterlife, although I must say after watching dogma and what dreams may come for the first time a few days ago, I did challenge my beliefs. They didnt change, but I gained a greater appreceation for them.
Perhaps not for you, but for most people, they desire to find a purpose and meaning in their life. I don't think I'm here just to work behind a desk for 8 hours a day to go home, sleep, and do it all over again with the goal of simply earning money to support myself until I die (excuse the cliche-ish-ness). Beyond the basic necessities (survival, etc.), human nature desires to find out why we're here. It's the universal question, "Why do we exist?!"
Why do you seem to insinuate that having a meaning and purpose requires a belief in the afterlife, and therefore possibly religion and god? I find no such requirement. I exist to change lives. I exist to provoke thought. My purpose and meaning in lives comes from the letters i recieve my readers of our newspaper, when they thank me for a picture I took, or tell me I did an exceptional job in conveying what needed to be said.
Purpose and meaning can certainly be obtained by what you do currently in your life. You can certainly die feeling fulfilled at what you have accomplished, fulfilled that your purpose and meaning have been found and met, without neccesarily requiring that you look forward to heaven. If I die knowing that I have changed ONE life for the better, made ONE person smile...I have succeeded in what I was born to do. And thats what matters.