Your boss doesn’t want you to discus your salary with your coworker; this has been drilled into you from the time you start working. The reasoning given comes in different forms. You may be told that it’s just unpolite to talk to other people about their income. You may be worried about coming off as nosy or braggadocios. But the one thing your employer is definitely worried about is if you discuss your salary with coworkers, one of you may find out that you aren’t earning your worth. The knowledge that someone who does a similar job makes significantly more money would certainly be a factor in a pay increase negotiation. Some employers have even gone so far as to make it against company policy to discuss your salary with coworkers. Some of them ingrain it into you that in fact, the reverse might happen. If you go in with a complaint that you don’t make as much as your coworker, your boss may just say, “Okay, we’ll lower his salary to be comparable.” With that threat, employees are less likely to complain, lest they gain nothing for themselves, while losing something for their colleague.