There are philosophical and practical reasons to go to work everyday. From the strictly practical, because you want the paycheck. There are things you want - like to get your own apartment, a car, being able to go to concerts, etc. And, then there are bills - rent, utilities, food, doctors, etc.
But, some people find a sense of self-fulfillment in their jobs. I worked in the state workforce center before retiring. I helped people to find jobs. These people often had lost their self-esteem and self-confidence. They were fired for bogus reasons, and had applied to dozens of jobs without ever being called for an interview. They didn't know how to write resumes. They didn't know how to explain in an interview that they were fired from their last jobs. I gave them hope. I gave them self-confidence. The job did not pay well. But, I know I made a difference in a lot of peoples' lives.
I hope this helps!