Job satisfaction is defined as a collection of attitudes next to your job. You like parts or all of it. It is important to measure it because in the study of organizational behavior is correlated with performance. Of course, a wise organization measures the satisfaction of its employee and takes action to improve it.
Going to work in the morning is related with happiness or at least a state of acceptance next to your job. You work 8 to 10 hours a day, you get paid, and then you get back to your life.
In the same time, job satisfaction is a necessary evil. Your existence is conditioned by the needs that you have and also the needs of those for which you are a provider. No matter how much we get, we want more. Is what drives us forward, being in the same time the root of our unhappiness.
No matter how much the organization does, in the end job satisfaction is a choice, an acceptance of your responsibilities with a reward that influences not if you go to work, but if you go to work at the same company next month.