Can people with a strong type of nervous system be unbalanced?

People with any type of nervous system can be unbalanced. Imbalance – predominance of excitement. Such people are better at showing external activity than holding back. Usually they say about such people: he said without thinking.
On the other hand, balanced people are very patient, even constrained.
Distinctive features of a person with a strong nervous system: high efficiency, mobilization, ability to take a punch, multitasking. However, they also have their limit in everything, like any person.