How can a 'passively aggressive' individual be a danger to themselves or others?

Repressed feelings: Sometimes holding your feelings in can lead to a bigger reaction than if you let it out little by little.

Passive Aggressive: You aren't an immediate danger but with time you hurt yourself and others by building walls up around you to keep people out or by people not wanting to get close. Its a means of manipulation that the person may be unaware of. "if you really love me then you would do this" type of pattern. Making people do what you want by making them feel bad, is as simple as i can put it.