How resources, skills and abilities make a difference. Japanese loved fresh fish but for decades close by water has not held many fishes. So to feed japanese population, fishing boats got bigger and went further and further than before. Further the fisherman went for fishing, more time it took them to bring back the fish. Because it took a lot of time to get back after catching fishes, fishes were not fresh and didn't taste good. Now, to solve this problem, fisherman started to install freezers on their boats. So that after catching fishes they could freeze them at sea and this allowed fishermen to go further and stay longer to catch more fishes. However, japanese could taste the difference and they didn't like frozen fish. This made fishing company think for further solution and installed fish tanks in their boats. Now, they would catch the fishes and stuff them in tanks. After little trashing around these fishes were tired, dull and lost their freshness. This lead fishing companies to face an impending crisis. Today, same fishing companies get fresh tasting fish to japan.. !! Wonder how they managed to keep the freshness of fishes?? To keep fishes fresh. Japanese fishing companies still put the fishes in the fish tank but with a small shark.. !! Because of shark fishes are challenged and constantly on move. This challenge keeps them alive and fresh. 
In our life new challenges keeps us active. If you steadily win challenges, you are happy. These challenges keeps you energized. 