Boundaries
“…you define your intangible boundaries and to recognize them as an ever-present reality that can increase you love and save your life. In reality, these boundaries define your soul, and they help you to guard it and maintain it.” Henry Cloud & John Townsend, Boundaries
Every person has boundaries. Boundaries are simply an agreement with yourself as to what kind of behavior you will and will not accept from others. This means a healthy and stubborn adherence to act in the best interests of all concerned, but yourself first. Besides, for these reasons, we also set boundaries to protect ourselves as well as to have a healthy relationship with others and ourselves. You simply cannot have a healthy relationship with someone that has no boundaries. Furthermore, you not only have the right, but you have a responsibility to protect and defend yourself against aggressive people who do not respect boundaries. 
Personal boundaries are guidelines, rules or limits that a person creates to identify reasonable, safe and permissible ways for other people to behave towards them and how they will respond when someone passes those limits.