While this applies appropriately to food, it applies to running as well. Everyone has mental limits in their head of what a human can run on a weekly or daily basis, regardless of the fact more is usually possible.
We are so programmed to think about scarcity, maybe it is a cultural thing, or a recession thing. And it does have some value, there is only so much oxygen in the world. There is a lot of oxygen, still on Earth there is only so much. The same can be said for land, there is a lot of it, but it is finite. What I like about those two examples of scarcity, more than the example of scarcity in my checking account, is that I don't think in either case a human can truly comprehend the abundance before we get to that scarcity. So it is the same with what is possible. In my lifetime I expect to see machines and vehicles that simply astound current notions of what that machine or that vehicle can do. There are limits, I don't know we will be defying gravity anytime soon, or traveling at the speed of light, but what is possible is likely far beyond our imagination. 100 years ago armies traveled by horse, train and foot. 50 years ago we could launch a missile across a continent and destroy a city, which thankfully never happened. Now one guy at his computer can steal a million credit card numbers.
The point being, we live in a time of relative abundance. Not abundance of everything, there are still famines in Somolia, shortages of Ebola vaccine, and food keeps getting more expensive. Yet, most of you read this blog for nearly nothing. The cost to access the Internet is quite low in terms of dollars per hour, probably a couple dimes an hour. There is abundance in this world, wether it is the variety of foods to eat, the miles one can run week after week, or the number of times parents continue to clean up after their kids.