Two of the women I work for fight every day, sometimes all day. They yell and scream and swear. I don't care, and sometimes they're funny, but one of my co-workers is reduced to tears every time it happens. Why would it bother her so much?

Your co-worker might be crying because your bosses' actions remind her of another time when she had no control in an upsetting situation. She might be thinking she'll be called on to take sides and end up feeling all the more uncomfortable. She might also be understandably concerned the situation will escalate into violence.

Given that this goes on all day, every day, it's a wonder your employers are still in business. Whether someone is reduced to tears or not, the work environment created by your bosses is unhealthy, unprofessional, and could be illegal.

While your employers have the right to fight all day long, they do not have the right to subject hired employees to their fighting. Since chronic upset of this sort often escalates into violence, your co-worker is right to be concerned and has the right to file a complaint with the appropriate authorities. She may even have the right to some form of compensation depending on the work conditions and any losses incurred by seeking employment elsewhere. She cannot, however, be fired or harassed for filing a complaint.

However, it doesn't sound like she is the type of person who would file a complaint. So, even though you find the situation funny rather than upsetting, have a little compassion for your co-worker and file it yourself. Start by filing a complaint with management. If you don't have the option of going over your bosses' heads (e.g. if the employers are also the owners), it would be appropriate to file a report with the police for the purpose of creating a paper trail, and call your state's Department of Labor for further resources.