The fourth Democratic presidential debate is over, and the most memorable moment may well have been an offhanded bit of condescension from former vice president Joe Biden aimed at Massachusetts senator Elizabeth Warren. 

Late in the debate, when she referred to the creation of the Consumer Financial Protection Bureau, he first yelled at her and then interrupted her, saying: "You did a hell of job at your job." It was a highhanded comment that sounded all too familiar to many professional women, including some of the CNN reporters covering the debate.

Personally, it reminded me of my 29th birthday. The man who was my boss at the time responded to the news that I'd turned 29 by saying I should consider that my biological clock was ticking. Sometimes, men can be condescending and offensive without having the slightest idea that's what they're being. 

That's what seemed to happen when Warren spoke about the creation of the Consumer Financial Protection Bureau, which was her idea, and of which she is justifiably proud. Biden and Warren have a long history of open disagreement, perhaps in part because she often targets big financial institutions and, well, he's from Delaware. But, in this instance, he seemed to want recognition for his participation. "I went on the floor and got you votes!" he shouted, gesturing at Warren who was standing at a podium beside his. "I convinced people to vote for it! So let's get those things straight too."

How much Biden supported the creation of the CFPB seems to be a matter of debate, with some who were involved recalling that Biden did not push for it, perhaps because of his ties to the banking industry. On the other hand, Jared Bernstein, Biden's economic adviser at the time, tweeted that the then-vice president was indeed a strong proponent.

Either way, Biden's comments were widely seen as an inappropriate attempt to grab credit for something his rival had spearheaded.

In fact, Warren's response to Biden's outburst was a master class in how to take control of a difficult conversation. Invited to give an answer, she paused for a beat, and then said: "I am deeply grateful to president Obama, who fought so hard to make sure that agency was passed into law, and I am deeply grateful to every single person who fought for it and who helped pass it into law."

Biden made himself look even worse by openly laughing during this statement. Then, as Warren went on to make her point, he interrupted her, saying, "You did a hell of a job at your job," and again gestured at her, coming within inches of patting her on the arm. Warren, ever unflappable, merely paused in her response and said brightly, "Thank you!"--which got a big laugh from the audience. Then she went right back to what she was saying.

To many female viewers, watching Biden talk to Warren was a reminder of the thoughtlessly highhanded comments they'd had to endure from men throughout their working lives.

Perhaps the most impressive thing about the whole exchange was that despite Biden's repeated interruptions, Warren never lost her cool, and she also never lost her focus. Instead, she went on to complete the point she'd set out to make about the importance of pursuing big goals. 

The CFPB "was a dream big, fight hard," she said. "People told me, 'Go for something little.'" Naysayers feared that opposition from the banking industry would scuttle her plans for the agency, but she stuck to her guns, and with help from the Obama administration, the law passed.

"We have to be willing to make big structural changes," she said. You may not like her politics, but that's a statement we can all agree with.