Standards are an interesting thing. They don't dictate exact performance, but they do sketch out a ballpark. If you expect yourself to read a book a week, you may not actually do that, but you'll probably read a book most weeks. If a boss tells you to have something done one month from now, you'll probably get it done sometime around then. Not two weeks earlier, but not two weeks later, either. Standards work to guide performance by creating an idea of what is acceptable and what is not acceptable. They shape our priorities, trying to maximize the amount of acceptable things we do and minimize the unacceptable ones.
It's interesting to think about where our standards come from. Why is forty hours a week the standard for a full week of work? Why isn't it less? Why isn't it more? Is that standard really right for everyone? Our societal standard for healthy eating is to eat anything that qualifies as non-dessert, preferably not entirely fried, and then a small amount of something that is dessert. Most people hover around that-- no one eats ice cream for every meal.