It is necessary most of all for one who is fasting to curb anger, to accustom himself to meekness and condescension, to have a contrite heart, to repulse impure thoughts and desires, to examine his conscience, to put his mind to the test and to verify what good has been done by us in this or any other week, and which deficiency we have corrected in ourselves in the present week. This is true fasting.
St. John Chrysostom
When anyone is disturbed or saddened under the pretext of a good and soul-profiting matter, and is angered against his neighbour, it is evident that this is not according to God: for everything that is of God is peaceful and useful and leads a man to humility and to judging himself.