The longer two tentacles have claws. Some important areas where the oceans are important to society are food, water, energy, waste disposal, transportation, military, and recreation. Most people live near coastlines for these reasons, and have for centuries. Most of the fish and shellfish of the oceans are there for the taking along the coast. The coastal mountains cause rainfall for fresh water, sea breezes power sailboats for fun and profit, and seaports harbored the great gunboats of Britania while it was ruling the waves and the submarines and aircraft carriers of modern navies.
Oceans moderate temperature variations.
It is no accident that coastal property values are much higher than those inland. Energy is the ultimate resource, and is very similar to money. Just as you can change money into various currencies you can change energy into various forms. The oceans affect our energy policies in important ways. Fossil fuels produce greenhouse gases, primarily carbon dioxide, and carbon dioxide is absorbed into the ocean by complex processes.