…don’t say anything at all.
That was something I heard from my mother more times than I can count. Here’s something else I can’t count: the number of people who don’t follow that supposed rule.
Really, where did this saying even come from? I’ve never met a single person who abides by this, including myself. It’s not really possible to avoid things that aren’t so nice. Maybe if everyone in the world was a nice person, but that’s not how the world is.
However, if this expression is referring to unnecessary mean comments, I could agree. Nobody follows it, but it makes more sense. If I found out someone had stolen from me, for example, I’m completely justified in calling them a thief. I wouldn’t be justified in calling them a slur like the n-word.
There’s also the possibility this expression just means not to say unkind things to someone’s face, which is the definition I chose to take with it years ago. Of course, I don’t think talking trash about someone behind their back is much better. Unless they’ve hurt you somehow (in which case, you’re probably venting more than anything), you’re more exposing your own character, not theirs.
Personally, I think this is one of those expressions that needs to die out. Regardless of what meaning it’s taken for, it really may as well be meaningless. Everybody is going to have something unkind to say about someone, and they will say it. It may be within reason. It may not be. But they will.