High Blood Pressure and Low Blood Pressure, which one is more dangerous?

As everyone knows, high blood pressure(HBP) is more than 130/80mmHg and if someone has been diagnosed with HBP by Dr., they should care about that since it could be many causes of getting worse all over the body.

However, I heard that low blood pressure, below 90/60mmHg, is also dangerous because it could lead to shock or could be symptoms of lack of nutrients and oxygen to our organs. 

So I wonder High Blood Pressure(HBP) and Low Blood Pressure, which one is more dangerous.