From a philisophical / metaphysical / social contractish standpoint:
Is each individual human 100% their own? Or, even a little bit, do we have some say in others’ lives – even in cases in which it would not hurt another? For examples: (A)Euthanasia, do we have a right to stop others will terminal painful illnesses from ending their lives? Or, (B) Drug Use, if someone wants to sit in their own house and do heroine all day long, do we have a right to stop them for no other reason than we think it is wrong and a waste of life?