The second night of the 2020 Democratic presidential debates has come and gone, with substantive discussion on issues such as health care, climate change, immigration, criminal law, and the economy. But this second debate also had its share of weird, wacky, and head-scratching moments as well, many of which can stand as lessons for every public speaker. Here are a few of the most surprising.

1. Biden calls a 54-year-old senator "kid."

Candidates took the stage in descending order of their polling numbers, which means that former vice president Joe Biden walked out first and senator Kamala Harris came out next. (Elizabeth Warren is ahead of Harris in the polls, but she participated in the previous night's debate.) When Harris arrived onstage, Biden greeted her with a jocular, "Take it easy on me, kid." It was a clear reference to their first debate in June, when Harris forcefully challenged Biden on his record on busing. 

It was cute, it was funny, it was typical Biden, and ... it was completely inappropriate. As New York Times reporter Maggie Haberman noted in a live blog during the debate, "Most grown women don't like being called 'kid' or 'kiddo' by, well, anyone but their parents." The fact that Biden used the term to address a 54-year-old woman who is African American just makes it that much worse. It was also one of many moments when he inadvertently reminded viewers that at 76, he was by far the oldest candidate onstage. (Vermont senator Bernie Sanders is almost a year older than Biden, but like Warren, he debated on the previous night.)

2. Biden reminds Gillibrand that she once liked him.

Perhaps unsurprisingly, Biden was taken to task on his record on gender equality by New York senator Kirsten Gillibrand, who questioned him repeatedly about a decades-old comment in which he apparently argued that women working outside the home would hurt American families. Biden, probably wisely, did not directly address his alleged former statement. Instead, he recalled a trip that he and Gillibrand had made to Syracuse in former and apparently friendlier times. "You ... said it was wonderful that I'm passionate about the concern making sure women are treated equally," he lamented. "I don't know what happened except you're running for president."

3. Gillibrand plans some housecleaning.

Speaking of Gillibrand, she got the biggest laugh--and product placement--of the evening during a discussion of climate change. In a line she had clearly been saving for the right moment, she said, "The first thing I'm going to do as president is I am going to Clorox the Oval Office." It was an easy shot, given the deep unpopularity of president Donald Trump in this particular crowd. She went on to say that the next thing she would do is reengage in the fight against climate change.

4. Bennet agrees with Castro while Castro is disagreeing with Bennet.

While answering a question about the Mueller report, New Jersey senator Cory Booker (who had a pretty good night) argued that impeachment proceedings should begin against Trump. This question of whether to impeach Trump or simply focus on defeating him in an election may be the most divisive issue in today's Democratic Party.

Colorado senator Michael Bennet argued for no impeachment, saying that the party should work to beat Trump at the polls. He warned that if the House began impeachment proceedings, the Republican-majority Senate would never vote to remove Trump from office, allowing Trump to claim he was exonerated. Julián Castro, Housing and Urban Development secretary in the Obama administration, argued forcefully against that position. His view is that to refrain from impeaching Trump would make it appear that the House failed to find any wrongdoing. "Conversely, if [Senate majority leader] Mitch McConnell is the one that lets him off the hook, we're going to be able to say, 'Well, sure, they impeached him in the House but his friend Mitch McConnell--Moscow Mitch--let him off the hook."

Now it may seem to you that Bennet was arguing against impeachment and Castro was arguing for impeachment. It certainly seemed that way to me and to pretty much everyone watching. Everyone except Bennet. "I don't disagree with that, you just said it better than I did," he told Castro. Wait, what?

5. Biden can't say his own URL. (Or did he mean text number?)

OK, we get it, Biden is old. But if he can't manage today's technology, that bodes ill for his campaign, not to mention his potential presidency. At the end of his closing remarks, he asked viewers to, "Go to JOE 30330 and help me in this fight," although he sounded a bit uncertain when he said it.

No wonder. It turns out the Democratic front-runner had confused the URL for his campaign the short code used to sign up for his campaign's texts. But even that wasn't quite right. Moments after the debate, his campaign issued a tweet inviting people to text the word "JOIN" (not JOE) to the number 30330. If he hopes to convince voters that he's the candidate for the year 2020, this kind of thing doesn't help.