The reason growth is positive for a country is thst growth allows current work to be more valuable then past work. The work done today is more efficient, more valuable then the work done 50 years ago. This is reflected in growth. Now, try to see the opposite case. Let's say what you are doing today is less valuable then what your parents did 50 years ago. Would you be doing it? Or would you move on to do something else? This can be seen, for example, in service jobs. When a sector doesn't grow significantly enough, people will no longer want to be associated with it. They won't want to work in it (dead end job), they don't won't to invest in it (no return on investment) and they don't want to buy the products and services (same old, we allready have this, it's becoming boring) which leads to the sector declining steadily.