The article analyses adjudication processes: decision-making, incentives, factual states and legal conditions influencing the content of adjudication. A practical solution to problems by adjudication and a custom as part of this practice. A custom can be defined as a non-legal habit of conduct virtually observed within a given organizational structure (unit) of administration in similar situations and in specified time.The society, including the bodies that govern it, should be characterised by legality, i.e. act within law. In our conditions an administrative decision is of phenomenal significance and leaves a clear mark on our everyday life. It is virtually impossible to meet a person that has never been a subject of an administrative decision. Because of the importance of an administrative decision in our life, this article is addressed to those clerks in administrative bodies that in the course of administrative proceedings draw up the content of a ruling or decision that terminates the proceedings in a particular instance and feel anonymous. Underestimating familiarity with law by stating that one does not know law or that one is not a lawyer is frequently repeated by those employees in administrative bodies that are responsible for the content of those decisions and in this way they reveal their ignorance. Ignorantia legis non excusat (Latin for “ignorance of the law excuses no one”), therefore one cannot excuse oneself with unfamiliarity with law.