A job is important because it is important to have money in order to survive in our world. Even without money, you can survive off of shelters, but they encourage you to get a job and earn some money on your own. It is also important because it improves your self-value. It means something to have money, and to have a job.
Job: defined for this question as a separate place - away from your home that a person commutes to. This person trades their time for money to buy 3-D TV's and houses with pools.
The government wants you to work so you will pay taxes and continue to help the government grow bigger.
If you grow your own food and live very cheaply (it can be done) you don't necessarily need a job. As far as adding self-value, I doubt it. If you seek self-value from someone, thing, or activity, you will not find it.
Self-value comes from one's self. If you don't value yourself - why would anyone else?