It is widely known that lying is a character trait we should avoid. As the Torah states, "distance yourself from falsehood" (Exodus 23:7). This might lead one to conclude that it's always permissible to say something that is true. However, are there times when telling the truth should also be avoided? Rabbi Joseph Telushkin poses this question - as well as a challenge:
Do you think you can go an entire day without speaking negatively of another person - even when what you're saying is true? Of course, this is easier said than done (no pun intended), but it's something that has the capacity to improve a person's character. If you happen to fail in avoiding unfair speech all of the time, it only proves that you're human. But if you're not even successful in avoiding unfair speech some of the time, it doesn't reflect well on your character.
The most important part of this whole idea is to imagine ourselves on the receiving end of our own conduct (i.e. follow the golden rule). Unless there is an objectively constructive purpose for saying something negative about another person, it is better left unsaid. A red flag should always be raised when we begin to rationalize as to why it's okay to speak ill of others. After all, rationalizing is nothing more than rational lies - and we are compelled to distance ourselves from such behavior.