Incidentally, the title to this two parter is a mnemonic phrase used by Jim Fay of the Love and Logic Institute. I think by "Save the words for the happy times' Jim largely meant to communicate the concept I'm calling the Attention Principle. If you're doing lots of talking when things are aren't going well, you are inadvertantly reinforcing behaviors you would like to see less of, but that because you're pouring on the words, you are going to see more of.
I like his phrase because it is brief and easy to remember. It sticks. But it does elide the fact that you can save the words not only for the happy times, but also for "neutral" or even just "more neutral" times. Beyond the avoiding inadvertent reinforcement the attention principle predicts, it also give the brain a bit of time to cool off. And finally and just as importantly as the others, it gives you time to think. When we make decisions in the heat of the moment as parents we're going to see painful, smoking bullet holes through our shoes more often than we'd like.
So assuming we manage to keep our words brief and not do a lot of talking when our kid is acting in a challenging way, what are we going to do when we circle back?
Your first best bet, however you decide to proceed is find out more about what was going on. Let's say the situation was that your tween was on the computer and when you asked her to get off. She did, but started screaming at you about how mean you are and slammed a couple of things around on her way to her room.