The Previous Rebbe related in the name of his uncle, Reb Zalman Aharon (the older brother of the Rebbe Rashab):

"When one becomes angry, he should wait at least sixty-one minutes, and then he can think clearly."

Igros Kodesh of the Rebbe, vol. 7, p. 116

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Our Sages of blessed memory taught: "Whoever is in a rage resembles an idolater."

The reason for this is that when a person is angry, faith in G-d and in G-d's individual Divine Providence have left him. For were he to believe that what happened to him was G-d's doing, he would not be angry at all. True, the person who is cursing him, or striking him, or causing damage to his property is doing so out of free choice and is therefore guilty of his evil choice according to the laws of man and the laws of Heaven. Additionally, the perpetrator of the offense cannot plead innocence on the grounds that he is merely an instrument in the hands of Divine Providence. Nevertheless, regarding the person harmed, this incident was already decreed in Heaven, and "G-d has many agents" through which He can act.

Tanya, Iggeres HaKodesh, Epistle 25