Boundaries are foundation to good physical, emotional, spiritual, and mental health. Without them one will find themselves always tired, spent, resentful, failing, sick, and far from their best self.
Boundaries can have a stigma in the minds of many of being a mean, harsh, uncaring wall built to cut people out of their lives. In reality, boundaries are natural, health, and they support everyone involved. One example of weak boundaries is co-dependence in which one person over-gives to another to try to help them. However, the sad news is that both people are dishonored in this situation. Neither will be able to reach their full potential or be their best self: one will feel overly responsible and resentful while the other dis-empowered and ashamed, etc.
Establishing healthy boundaries brings about all kinds of wonderful changes, and I believe reaching optimal health cannot be achieved without it.