If there's no god, then there's no one to bail us out. It's up to us as individuals to make a society in which we would want to live. It's up to us to not waste and to not use more than we need and to not fuck up the planet. I want to live in a society where I can get help when I need it, so whenever the opportunity comes my way I will help out others, and will go a reasonable amount out of my way to do so. If I have more than I need I will share it freely. I will recycle, only purchase what I will use and need, use public transit when I can, drive a hybrid or other more fuel efficient car, plant my own vegetables, buy local, smile at whomever I pass in the street, and say "thank you and have a great day!" to the driver when I get off the bus and to the dude who makes my breakfast. I will treat people working in the service industry and homeless people and ALL people with the same respect and dignity that I give my students and colleagues. I will tip at 20% or higher. I will do my best to not actively make the world a worse place for other people. I will pursue a career in which I can promote understanding and social justice and equality, and in which I can help people improve their own lives.
We're the only ones we've got. This is the only life we got. All we are is how we impact other people on this earth. That is our legacy. All we have is one short life that could end at any moment. If we're lucky we can leave the world a better place when we're gone.
In our house we have a plaque with a Shakespeare quote that we found out on the curb somewhere when we lived in Philly...it's a pretty good summation of my moral code: "Love everyone, trust a few, do wrong to none"