ДАДУТ ДУРАКУ ЧЕСТЬ, ТАК НЕ ЗНАЕТ, ГДЕ И СЕСТЬ

There is no one so arrogant and demanding as an unprincipled person. See Дай волю на ноготок - он возьмет на весь локоток (Д)

Cf:Give him an inch and he'll take a mile (an ell, a yard) (Am.,Br.) Give knaves an inch and they will take a yard (Br.)