If you watched last night's presidential debate, chances are you didn't learn much about the issues facing our nation. With three hours of debating now under their belts, not to mention thousands of hours of stump speeches, Donald Trump and Hillary Clinton have already said every sound bite they have to say.

Last night's debate was especially vitriolic--so much so that CNN dubbed it the "scorched-earth debate." If you just listened to what the candidates said, there wasn't much of anything new. But if you watched their body language closely, both candidates revealed more about themselves than they bargained for, and not in a good way.

To help parse out the body language messages of last night's event, we enlisted the aid of Janine Driver, president of the Body Language Institute, and a retired federal officer who specializes in deception detection.

Here are some of the body language goofs she spotted, and that you can learn from:

1. Refusing to shake hands makes you look weak.

Breaking with many years' tradition, the candidates did not shake hands at the beginning of the debate. It was subtle enough that you could easily miss it, but if you watched closely, you could see Clinton saying "Hello, hello," coldly to Trump and then turning away before he could approach her to shake hands. He wound up taking an awkward step away from her as she turned to face the audience.

Unless you've spent the last 24 hours away from all news and social media, you likely know that Trump has been vilified for a taped conversation in which he brags about being able to grope women as a star. He responded by assembling several women who have accused Bill Clinton of sexual harassment and giving them prominent seats at the debate. The move appears to have gotten under Hillary Clinton's skin.

"I might have coached her to shake the hand," Driver says. "It looks to me that by snubbing him, she shows he has shaken her up a little." Driver also spotted Bill Clinton looking at their daughter Chelsea with a sad expression right before the debate began. Chelsea herself looked near tears and gave her father several reassuring arm touches as they sat down. So it may be the entire Clinton family is rattled.

2. It's still rude to point.

We were all told as children not to point at other people and it's still good advice. Hillary Clinton has been "a pointer" as Driver puts it. But she appears to have had some coaching and during the debate she did not point at Trump even once. He, on the other hand, pointed at Clinton over and over and over. It did not play well.

3. Smiling at the wrong moment makes you look smug.

Hillary smiles so much that she had what Driver refers to as a "permasmile." Smiling, of course, is powerfully positive body language but too much of it is a bad thing. Perhaps because of coaching, Clinton has not had a constant smile pasted to her face lately.

But during last night's debate, whenever Trump came out with a particularly harsh criticism, Clinton responded with a huge grin. "It was like an alarm going off," Driver says. The effect on those watching, she adds, was to make Clinton seem smug, especially combined with her frequently raised chin, another sign of feeling superior. It's a simple rule: Save the smile for times when a smile is called for.

4. No matter how threatened you feel, don't clasp your hands in front of you.

If you're under attack and feel intimidated, it's natural to assume a defensive posture, making yourself small and perhaps clasping your hands in front of you. But when you clasp your hands in front of you, it tends to look like you're trying to protect your private parts, making you appear even more defensive and weaker, as Trump did during the discussion of his lewd audiotape. It's not a good look.

5. Pacing is always a bad idea.

Clinton would often walk over onto Trump's side of the stage and sometimes into his space. "That's dominant," Driver says. "I'd bet a million dollars she was coached!"

Trump was clearly rattled as a result. To get away from Clinton's encroachment, he walked toward the back of the stage, grabbed the back of his chair and began pacing in an almost threatening way. "I teach a pre-assault class to law enforcement, and pacing is one of the top three pre-assault indicators," Driver says.

Obviously, Trump would not physically attack Clinton on national television, but his walking around behind her appeared threatening played very badly as this Twitter exchange shows.

And here's one brilliant subconscious verbal signal:

6. Use 'don't' when you mean the opposite.

It's a powerful subconscious message, Driver says. "When you say don't do something, it becomes an embedded command. 'Don't turn around and look who came in this restaurant.' When you add the 'don't' it becomes twice as strong."

So check out this comment from Clinton near the end of the debate, in answer to a question as to how the candidates would lead all Americans, even those who hadn't supported them: "If you don't vote for me, I still want to be your president."

That phrase "don't vote for me" in the middle of the sentence was an embedded command to do just that, and a very effective one, Driver says. "Without a doubt, it was planned."

Will it actually lead people to vote for her? A month from now, we'll all know.