you never think the last time is the last time.
you think there'll be more.
you think you have forever...
...but you don't.
The Prophet Muhammad (peace be upon him) said, "Do you know what backbiting is?" They said, "Allah and His Messenger know best." He then said, "It is to say something about your brother that he would dislike." Someone asked him, "But what if what I say is true?" The Messenger of Allah said, "If what you say about him is true, you are backbiting him, but if it is not true then you have slandered him." (Muslim)
Allah cautions against backbiting in the Qur'an: "O you who believe! Avoid much suspicion, in deeds some suspicions are sins. And spy not neither backbite one another. Would one of you like to eat the flesh of his dead brother? You would hate it (so hate backbiting). And fear Allah, verily, Allah is the one who accepts repentance, Most Merciful." (49: 12)