Boundaries are open and honest communications that set limits to what we will and will not accept in a relationship as individuals... these are easy for the emotional intimacies you closely agree to but when it becomes abusive in a combative exchange they are critical to ensuring that our values are not just heard, but seen.What do you mean boundaries? Sorry. Lol.
For example, you are with someone who begins fights in public places and instead of engaging in a combative environment you clearly state that you do not wish to have such a discussion in public and you will readily continue any discussion concerning such in private, you have now set a boundary. If the other party insists on continuing the altercating conversation you then state that you will no longer be in their company if they cannot respect your wishes and leave... now you have enforced that boundary.
Boundaries must be something that you can stand a test of moderate time with... they cannot be short-term and must be value applicable to the situation.
If you crumble it at your feet with the first challenge, you will be teaching others the wrong thing... it must be fair, and it must be consistently applied.