We are still here, as human beings, because millions and millions of us - since far, far longer ago in our history than recorded time - have looked at the world, and said "I want my children, and my children's children, to have a better life than I did."
Maybe your parents and your grandparents and great-grandparents were among those people - or maybe they weren't, personally. Some people admittedly aren't.
But every human alive is part of an uninterrupted line of hundreds of thousands of years of descent (and that's only since we became Homo sapiens).
We, as humans, have created and built and invented and learned and treated and cured so, so much. Because we kept looking around us, and looking at the people around us, and saying, "I want a better world for the people I love. I want a better world for the people who will come next."
Or perhaps think about it this way:
Would you want your great-grandchildren (or the great-grandchildren of your loved ones / family / chosen family, if you'd rather) to be miserable?
Or would you want those children to take care of themselves, and be kind to themselves, and do their best to find peace and joy in their lives?