Hippocrates famously said: “Make a habit of two things: to help; or at least to do no harm.” Add one more important habit to his list.
Never mind that he didn’t actually say any such thing….
But as long as doing helpful things and refraining from doing harmful things is the topic, let’s go back to another ancient source, a fellow named Siddhartha Gautama. He taught that we would be happier if we followed eight habits, including seeing the world as it really is, paying attention why we want things, saying the right things (not saying bad things), doing the right things (again, not doing bad things), having a job that is good for the community or mankind (yeah, maybe “assassin” isn’t a proper career path), putting a good effort into all we do, being aware, and focusing on things where appropriate.
You don’t have to believe everything he said to think those are good ideas.