When someone is sober, it means that person is not drunk or under the influence of any intoxicating agents such as alcohol or drugs. It is also used to refer to when people are serious, solemn, and in their right senses.

sober

In most cases, people who are not sober; under the influence of any form of drug or alcohol can act on impulse, be unstable both mentally, emotionally and otherwise. It can make them aggressive which sometimes may result in getting involved in a fight. Also when people are not sober they might say things that they cannot say when they are sober.

It is important to realize that staying sober would make you be aware of who you are, what you are doing at every point in time, what you are saying, and how you are reacting to situations around you. 

Kelly Smith