My wife and I trained the dog to gently push the cat away from the dog food bowl. It's not that we don't want the dog to share, it's just that the cat is fat and has asthma which is worsened by his weight problem.
My dog likes to whine a lot. I take the dog out, I give the dog water, I give the dog food. The dog lies down on the floor next to her food. She is guarding her bowl. She isn't whining anymore. She has purpose. She has a job to do, to save the cat from his own gluttony.
Like my dog, we humans need something to occupy our time, but specifically something to give us purpose. Without purpose we become bogged down in the misery of the world's tragedies. And even if the world were perfect, without purpose we would find some reason to be miserable.
Misery -boredom, depression or just that feeling in your soul that something is missing- leads to all sorts of problems; addictions, overeating, war, crime, reality T.V., Paris Hilton. If we hate these things and desire to have better lives then purpose is the answer. Purpose. Purpose.
We could even add to the list -beyond purpose- is the need to be needed. Feeling like you are needed gives you purpose. I am needed here so I shall stay here and fulfill my purpose. So, you could say that being needed is the seed that grows into purpose. Yeah, I like that.
Bare in mind that being needed is perception. You do not need to be truly needed. All you need is to think you are needed. This may be difficult to accomplish. It may even require a bit of brain washing on your part. This may even become dangerous in that when you discover you 'needed'ness was really false all along you may find yourself come crashing down into a mire of misery. Be careful.
This is how the whole world turns. Being needed, having purpose. Marriage. Children. Jobs. Serial Killers. Rock bands. Everyone needs to be needed and being needed gives everyone purpose. And purpose in the meaning of life. If only the system were perfect.