Mala fides: improper motive in administrative action requires factual proof and cannot rest on mere assertion. Mala fides denotes a want of good faith arising from personal bias, improper motive or ulterior purpose; it must be proved by facts and circumstances, not mere assertion, and contrasts with malice in fact (ill will or spite) and malice in law (wrongful or wilful act without lawful excuse), the latter being the form attributable to the State where personal ill will is not applicable.