This life is all that we have. Make the most of it and do not belittle it with a promise of reward after you die.
Life is it's own purpose.
This!
This one life is the only one we KNOW we will have. Could there be something after death? Sure, but with no concrete evidence, it is not certain.
I feel like everything we experience, good and bad, is precious because it is so fleeting. A human lifetime goes by in a blink of an eye. It should be cherished.
To me saying this is just a means to an end (heaven) is rather sad. Life is precious and to say that our spin on this rock is only a waiting game for the afterlife cheapens the human experience.
"Yesterday is History; Tomorrow a Mystery; Today is a Gift, that's why it's called The Present."
This is my opinion, and I'm not trying to sound callous. If belief in the afterlife gives you comfort, great, but just think about what I said. You should appreciate the life you have, as it is the only one you are CERTAIN to have. You could be right and there could be a heaven, but that doesn't make this life less precious. Don't waste your time focusing on what comes after, enjoy what is now.