The use of a discretionary power cannot lead to arbitrariness. A public authority must always have good reasons for choosing one course of action rather than another. A normal part of exercising a discretionary power is to explain the reasons why a particular course of action has been chosen. Furthermore, when making a discretionary decision, an institution must act within the limits of its legal authority. Very broad discretionary powers may exist, but they are always subject to legal limits. General limits on such authority are established by the case-law of the Court of Justice. This requires, for example, that administrative authorities should act consistently and in good faith, avoid discrimination, comply with the principles of proportionality, equality and legitimate expectations and respect human rights and fundamental freedoms.