Boundaries are so important. I know you've heard this term a thousand times and are sure you have implemented them, but do you really understand what they are about? Think about a time when you have felt uncomfortable in a situation. Someone did something that affected you physically, mentally, or emotionally. How did you address it? This is what boundaries are all about. You create, establish, and maintain a rule, that helps make you feel safe in an uncomfortable situation. The best example to clarify this would be pointing to hard and soft limits. Boundaries are created to make sure you feel safe, comfortable, and cared for. They are created to avoid uncomfortable situations that may put you out of your element. Hard and soft limits in BDSM can very much be associated with boundaries. However, BDSM is not the only area of our lives to have boundaries for.
For example, someone sits next to you on a subway train. They slowly start to scoot closer, and closer, even though there is clearly space on the other side of them. What do you do? Set a boundary. " Excuse me, you are making me very uncomfortable and I would appreciate it if you would move back over, and stop moving so close to me. " This is setting a boundary for them as well as giving them the why behind it. It also allows them to respond. If they react negatively and refuse to comply remove yourself from the situation and away from them.
A relationship example: You just came home from a hard day at work, you enter the kitchen and immediately your spouse/partner begins to say things like why is the kitchen a mess, why is the house not clean, you look fat in that outfit..... The boundary setting for this scenario would include something like, " I understand that you are upset, but I just got off work and would like time to compose myself before we discuss the house and anything that needs to be done. I do not feel comfortable with you pointing out or making negative statements about my appearance, so please refrain from doing so." You are asking not to be confronted immediately with problems after work, you could probably clarify with something like work stresses me out I need time to decompress or I have a lot on my plate at work, and need time to wind down and de-stress. You're letting them know that they should not be making negative statements about the way you look and the why behind it.
Boundaries should always be respected, and adhered to. Just like someone adhering to your hard and soft limits, what you say goes. If a person does not respect your boundaries it is an immediate red flag, and you should respond by doing what is best for you in that situation. It may or may not involve actions like blocking them, leaving, or filing with the legal system after repeated offenses. Boundaries can be confusing, but they are important because they keep you safe. Below I have included a link to a video that can help clarify boundaries better than I have here.