"Give us this day our daily bread." (Matthew 6:11)
The petition was and is counter cultural.
In the first century context, it spoke directly to the daily reality faced by the poor. Daily bread, that needed to live another day, did not come easily. Day workers, such as those depicted in the parable of the owner and the workers for hire, lived from day to day. Taking one day at a time was not a maxim but instead harsh reality.
By contrast, upper classes with property, prosperous businesses, government connections and the like lived in a long range world. Holding on to what they had and adding to it preoccupied many of them. They did not have to worry about bread for the day, but they no doubt invested considerable energy in trying to build their holdings and pass them along to their children.
At the risk of oversimplification, the two classes felt different needs. The poor might well have prayed "Give me bread for today." Those better off might well have prayed "Prosper my investments." The first is a prayer of acknowledged dependence, the latter at best invites God to help grow the family business.
Jesus' choice of phrase is congruent with his contention that God loved the poor and that riches make it difficult to choose to depend upon God.
The term "us" is important. It challenges the tendency of poor and rich alike to settle for self-centeredness. Positively, it pushes us to care not only that we and our loved ones (or "folks like us") have enough to eat (and by extension, have enough of the basics of life), but that others do as well. Personal acts of charity and sacrifice ensue. The more we grapple with the matter, we realize social, legal, business and government structures must also be addressed.
Let's not forget the question of "enough." With rare exceptions, humans act out of insecurity, both real and imagined. We find it hard to know and admit when we have enough of anything. The prayer calls us to scale back expectations, to recognize that each day is all we have, and to live accordingly. Obviously, when we do so, there's more to go around. Less obviously, when we do so we begin to free ourselves from slavery to pointless anxiety about the future. We start to become people more nearly able to live in the present moment.