I’ve done it. The one I feel worst about, and yet was quickly forgiven, was when I was working at the factory one day and our supervisors kept threatening us with overtime. I was sitting at the table with some co-workers and I mumbled something about “if they tell us that one more time, I’m going to hang myself. That’ll teach 'em.” I get a sharp elbow to the ribs and I look up, annoyed, at my seatmate, only to suddenly realise that sitting across from us is a kind lady whose son had hung himself a couple of years before. I felt like the biggest asshole in the world, and I stammered, sincerely and earnestly, an apology, but the lady was an absolute saint. I know it did still haunt her, as she couldn’t speak of him without tears coming to her eyes, however, she looked me directly in the eyes and smiled, and told me gently that it was okay, she knew I didn’t mean anything. I still felt like an asshole, but I felt like a forgiven asshole. And she was still just as kind to me afterwards as before. But good god damn.
These days, now that I am forced to deal with the public on a regular basis - not just any public, but pregnant public (!) - I overshoot. ie:
“Oh, what a beautiful baby! Was your labour quite long?”
“Why, I’m his grandmother!”
“Impossible! You look so young!”
“Oh, why thank you!”
Or:
“I’m glad to hear your baby is getting better. You look very pretty today, as well. How is your partner feeling?”
“She’s doing great, thanks.”
Or even, with a baby, I wait for cues as to the sex of the child: I will admire, coo, and then say, simply:
“How old?”
“He is three months.”
“Oh, he’s beautiful!”
So far, so good, and my customers think I’m a sweetheart. 
And I avoid much talk of hangings or death. 