Job is simply a regular work a person does in order to earn a living. The only reason why we commit ourselves to a job is because we know that after every successful completion of all tasks embedded in the job, we are going to get paid.
The pay we receive is actually one motivational force that keeps pushing us into wanting to find a job to do. Today, if you don't have any job, you would be called a lazy person. Another thing that can make someone to be proud of his job, is the uniqueness and usefulness of the job, that is why you see lawyers, doctors, engineers not having the same level with teachers, carpenters.
People engage themselves in different types of job. Some jobs are professional in nature, which means you need a specific period of training before you can start practicing it, while some are just casual in nature because you don't really need a wide level of professionalism before accomplishing the tasks embedded in the job.