Everyone is not raised the same and some people are not raised at all, frankly. Those who were taught to be respectful to others, be kind and other manners such as being careful about the way you speak to people, will often find themselves in displeasing situations with other adults who do not subscribe to the same principles.
Unfortunately, the one aspect of adulting that I was never taught is the need to teach people how to treat me. I have had experiences inside and outside the workplace that literally leave me astonished. While in the workplace, we need to communicate with people who we would never speak to if we weren't getting paid. This may sound harsh, but it's an honest statement. In our personal lives, we can choose our friends, but we usually cannot select our co-workers and bosses. This creates the issue of really needing to teach people how to treat you. In my experience, this is done by establishing and reinforcing personal, and professional boundaries.
Here are some key tactics I have used:
Set appropriate boundaries: if someone is doing something that makes you feel uncomfortable, disrespected or any negative emotions, address it! You owe it to yourself to ensure you are mentally stable and that stability is not possible if you are working and living in an environment that is healthy. This cannot be done in a toxic environment that is making you feel uncomfortable every day.
Reinforce those boundaries: When someone violates your boundaries, the only manner to stop them from doing it, time and time again, is to reinforce your boundaries. This can be as simple as having a conversation to reiterate the boundary itself. Depending on how severe the violation is, this could also mean notifying the person of the consequences of not abiding by your boundaries.
Stand by established consequences: If you tell someone that you will end a relationship if they do not stop a behavior, the next time they repeat the behavior you have no other choice but to end the relationship. It's similar to telling children "if you keep doing that I will put you on punishment." If you don't place them on punishment, they will never take you seriously and will just continue the same behavior. Everyone has to have consequences for inappropriate behavior and in order to maintain your sanity, you need to be sure to follow through on your commitment. It is the only manner to ensure your boundaries are respected. Also, remember to never express a consequence you are not committed to. Consequences are not threats, they are commitments that need to be achieved.
Be sure to take care of yourself and really think through what boundaries you need to remain sane. You are worthy of being respected, highly regarded and honored, in your personal and professional life. You can ensure this occurs by setting boundaries when needed and reinforcing those boundaries. No one has to agree with your boundaries, but they are required to comply with them.