If you've held a job or two usually you can clearly determine right away if you enjoy the job or feel that it's just a job. If you lean more towards disliking your job there are a few ways to tell if it could be doing more harm than good.
When working a job that you dislike it's one thing but when you have to go the extra mile of giving yourself mental pep talks just to get yourself to physically go into work, it may be time to rethink having the job. If you find yourself miserable from the time your at work to the time you leave, it could lead to a completely different you. Working a job that you can't stand could be putting you on edge during and outside of work.
Cold glares, rude remarks, eye rolling, disgusting attitudes and constant irritability. Bringing work home with you in this way is never good.
Another factor is the way you feel about yourself after leaving work. When you leave work feeling worthless, unappreciated, as if you've been putting in more work than what you get rewarded or disrespected by co-workers, employees and customers it's time to question where you work.
In some jobs, it's a given that there will be rude customers aiming their verbal aggression towards you but if you feel like it's affecting how you feel about yourself, don't force yourself to put up with it. It doesn't mean that you don't have thick skin or are too sensitive, it shows that you care about yourself and self-worth so much that you refuse to work a job that will constantly leave you going home in misery.
There are many people who work the jobs they hate just to have a source of income or for a decent paycheck to support themselves. When you really take a step back and examine how the job you work could be affecting other areas of your life and how you feel about yourself, ask yourself how much worth the job has. See if it's doing anything for you besides rob you of your happiness and using you as a doormat and underpaid servant.
Don't settle for the job that makes you feel like crap. Apply for the job you want and refuse to lower your standards of what you're looking for within a job.