Nice post above from somebody who quoted the Cathechims on when anger becomes a grave sin. Also, remember Jesusā Sermon on the Mount, where he said:
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You have heard that it was said to your ancestors, āYou shall not kill; and whoever kills will be liable to judgment.ā But I say to you, whoever is angry with his brother will be liable to judgment, and whoever says to his brother, āRaqa,ā will be answerable to the Sanhedrin, and whoever says, āYou fool,ā will be liable to fiery Gehenna.
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The note on that verse says:
Anger is the motive behind murder, as the insulting epithets are steps that may lead to it. They, as well as the deed, are all forbidden. Raqa: an Aramaic word reqaā or reqa probably meaning āimbecile,ā āblockhead,ā a term of abuse. The ascending order of punishment, judgment (by a local council?), trial before the Sanhedrin, condemnation to Gehenna, points to a higher degree of seriousness in each of the offenses. Sanhedrin: the highest judicial body of Judaism. Gehenna: in Hebrew ge-hinnom, āValley of Hinnom,ā or ge ben-hinnom, āValley of the son of Hinnom,ā southwest of Jerusalem, the center of an idolatrous cult during the monarchy in which children were offered in sacrifice (see 2 Kings 23:10; Jeremiah 7:31). In Joshua 18:16 (Septuagint, Codex Vaticanus) the Hebrew is transliterated into Greek as gaienna, which appears in the New Testament as geenna. The concept of punishment of sinners by fire either after death or after the final judgment is found in Jewish apocalyptic literature (e.g., Enoch 90:26) but the name geenna is first given to the place of punishment in the New Testament.
usccb.org/nab/bible/matthew/matthew5.htm