When you set healthy boundaries, you start attracting other people who set healthy boundaries also--and who will respect your boundaries because they want their boundaries respected in turn. Otherwise, you'll attract those people who would treat you like a doormat and not respect your boundaries.
ETA: Also, if you tried to set healthy boundaries as a child and those were violated or ignored, then it's going to be difficult to know how to set those healthy boundaries and NOT have them violated or ignored. But it is possible.
ETA2: And, maybe, as a child, SiFe sees those violations of boundaries as part of their social duty, along with other social data they take in (I'm expected by society to put up with these sorts of violations from certain people in authority); while NiFe sees those violations of boundaries as a statement about their personal worth (I'm being treated this way because I'm worthless, so I must prove my worth so people will treat me better).