What is the ruling on uttering the phrase: "Life is not fair"?

The saying "Life is not fair" is a form of reviling time (ad-dahr), which is forbidden. Life and time are merely temporal circumstances for what Allah decrees within them; they have no independent role or effect. Complaining about them is complaining about Allah, the Creator of creation and the Disposer of affairs, as stated in the Hadith Qudsi: "The son of Adam harms Me when he says, 'Oh, the misery of time!' So none of you should say, 'Oh, the misery of time!' for I am time." This phrase also indicates dissatisfaction with Allah's decrees. Whoever is content will be granted contentment, and whoever is discontent will be met with discontent. True comfort lies in being content with Allah's management and submitting to Him.