8. Nature of the job might be private
For some people, the problem isn’t that you have a second job; it’s the nature of the second job that may cause your employer to pause.
For instance, your second job may be nothing like your regular job.
For instance, moonlighting at a nightclub might cause your employer to worry about your level of rest. You might be too tired from working long hours to perform at your best.
Other employers might be upset if you are using skills based on training they provided to obtain secondary income. In some cases, there could be a conflict of interest because of the work you do.
For instance, you may fix computers for your day job but also fix computers on the side. Your employer might not approve of this arrangement especially if he or she believes you might be luring company clients to your side operation.
On the other hand, some jobs just might be of personal interest and not something that necessarily ‘fits’ with your day job and your professional reputation. That doesn’t necessarily mean you need to hide the work you do, but you also don’t have to advertise something that could easily be kept private. Whatever your second job might be, if you keep it a secret, it is less likely to interfere with your main job.