Intoxication
One of the goals of responsible service is to keep people from becoming intoxicated (markedly diminished physical and mental control resulting from consumption of alcohol and/or other drugs). Preventing intoxication among your customers requires understanding how alcohol affects people and having procedures in place to check and pace service.

A change in behaviour is more meaningful than a specific behaviour.

By being attentive to the behaviour changes of individuals you are able to identify potential alcohol issues more confidently.