“Fear of what other people will think is the most paralyzing dynamic in business and in life. You will never own the future if you care about what other people think,” said entrepreneur Cindy Gallop at the 2015 Fortune Most Powerful Women International Summit in London this week.  That comment captured the breakthrough spirit and high energy of the 150 women leaders who convened for Fortune’s fourth annual MPW conference in London. Trolling the C-suites of Europe, Fortune’s editors brought in Banco Santander SAN chair Ana Botín, EasyJet EZJ CEO Carolyn McCall, Newton Investment Management chief Helena Morrissey and Aberdeen Asset Management chief investment officer Anne Richards. We added some U.S.-based global operators such as Ingredion INGR CEO Ilene Gordon and Federica Marchionni, the new chief of Lands End LE . And from the upper reaches of power politics, we injected Australia’s former Prime Minister and Israeli’s leading voice of opposition. To mix it all up, we included MakeLoveNotPorn.com founder Cindy Gallop and around-the-globe rower Roz Savage.  As chair of Fortune MPW International (that’s me, Nina) and co-founder and executive director of Fortune MPW (that’s me, Pattie), we work closely on this annual conference, always hoping to top the previous year. We agree on some things and not on others. So we figured it would be fun to compare notes right in front of you, and share our highlights—and a few lowlights from this year’s MPW International Summit.  Pattie: EasyJet CEO Carolyn McCall really impressed me. Being an American, I knew hardly anything about her improbable success story. After 24 years in media, she quit her CEO job at Guardian Media Group to head Europe’s No. 2 budget carrier to Ryanair RYAOF , which was in serious trouble when she arrived in 2010. Since then, easyJet’s revenue has nearly doubled, profits have multiplied, and the stock price has more than tripled. How’d she do it? By zeroing in on customer service. If you’re not good to customers, “you’ll never have as much profit as you should have. It’s the bedrock of any business,” she told the MPW audience. She’s a tough boss who projected an, um, easy charm in our on-stage conversation.  Nina: For all of her accomplishments, I found McCall incredibly down to earth and easy to relate to. I also like her fundamental advice—she turned around this company by rolling up her sleeves and learning everything about operations. You can’t run a company from the confines of the C-suite.  Pattie: My favorite interview that you did was with former Australia Prime Minister Julia Gillard.  Nina: We don’t dwell on sexism at MPW. So I wrestled with how to approach that interview. But there is no getting around it, for all of her achievements as Prime Minister, Julia Gillard is remembered by the world for her 2012 “misogyny speech,” which has 2.7 million views on YouTube. She stood just feet away from opposition leader (now Prime Minister) Tony Abbott and, for 15 blistering minutes, accused him of sexism. Watching the speech, I was struck by its rawness of emotion—as if all the slights she had endured as the country’s first female Prime Minister had gathered into a volcanic eruption at this one very powerful man. Did she have any regrets? “No!” she blurted, as the room of MPW erupted into cheers.  Pattie: You brought out Gillard’s fierceness and fortitude. You did the same with Israeli politician Tzipi Livni.  Nina: I was so proud to bring Tzipi Livni to our stage. Despite her pitched electoral battles with Benjamin Netanyahu, Livni is allied with the newly reelected Prime Minister on combatting the rise of anti-semitism in Europe and a worldwide boycott-disinvestment campaign aimed at their economy. And on the nuclear talks with Iran, she may not be as outspoken as Netanyahu, but she remains deeply concerned about Iran getting nuclear weapons and suggests that the Obama White House isn’t sufficiently taking Israel’s concerns into account. On a more positive front, she sees new alliances with Arab states because of the growing threat of ISIS and Al Qaeda.  Pattie: You also interviewed a bunch of prominent women in financial services. I remember you insisting that we had to include “fintech” on the MPW International agenda—and each time you invoked that word, I’d envision some new-fangled Chinese soup…  Nina: This topic grew out of my conversations last year with Citigroup’s C Mahnaz Safa. And even if it’s a strange new term for Americans, Londoners see it as central to their economic future. Passion Capital’s Eileen Burbidge describes the sector as “digital innovation applied to finance.” You take the headquarters of 300 of the world’s largest banks, combine it with a booming start-up culture, and voila: Wall Street meets Silicon Valley. And here’s what I learned: This is a silver linings story. When the post-2008 credit crunch hit, Europe’s creative minds filled the void. Free-market innovation.  Pattie: Yes, the UK is ahead of the U.S. in fintech and also in board diversity. All three panelists in the Boards session that I led said they favor quotas to help make corporate boards more diverse. Coming from America, where there’s hardly any support for quotas, I was stunned. I have to admit, the Boards panelists practically convinced me that quotas are a good thing. Sophie L’Helias, a corporate governance expert and senior fellow at the Conference Board, explained that after France enacted quotas, the first round of female directors who came onto boards was not so impressive. But the quality of female board members has risen significantly, as have methods of evaluating directors—not just woman but men as well. As a result, diversity quotas have made corporate boards in France more accountable.  Nina: I should remind you, Pattie, that Newton Investment Management CEO and 30% Club founder Helena Morrissey told us she is anti-quota. Quotas don’t create lasting, sustainable change, and she noted that quota-happy Norway has no major female CEOs. And, by the way, quotas are a political nonstarter in places like the U.S. I’m with Morrissey; there are better ways to achieve board diversity.  Pattie: Talk about not giving women an advantage. Ana Botín didn’t get any on the way to the top of her father’s Santander banking empire, as your interview with her revealed.  Nina: Yes, Ana Botín rarely talks to the press, so it was a real treat to have her on stage. I was blown away by her quiet power. She made clear to us, contrary to the public narrative, that she was not tapped by her late father to run this bank. As a Harvard grad and JP Morgan alumni, she had to force her way in before proving her banking prowess. When she was forced out in 1999 after a magazine profile infuriated male execs by declaring her Spain’s most important woman, she learned a lesson about being careful with her public image. Knowing all that, it comes as no surprise then that she had the grit to start dismantling her father’s leadership team within months of taking over—determined to modernize an institution that four generations of Botíns have run. Next time, I want to find out what Warren Buffett, whom I understand she consulted, told her in private along the way.  Pattie: My philosophy for a successful on-stage interview is: Always leave the audience wanting more. Most of the time, we don’t get to ask all the questions we want to ask, which leaves us, as journalists, hungry and happy to stay in the game.  Nina: We heard incredible stories from these powerful women, but to me the most inspiration came from [Fortune senior editor and MPW co-chair] Jen Reingold’s interview with Roz Savage, who rowed a small boat across an ocean and not only lived to tell about it—but did it again! Her lowest emotional points along that journey—when her paddles broke, when her stereo crapped out, when even her satellite phone died—were moments that we can all relate to, even if not at that extreme. What do you tell yourself to keep going?  Pattie: These women we brought together are certainly are strong. How about Martha Lane Fox? This famous British entrepreneur founded and built Europe’s largest travel site, lastminute.com, and sold it for a lot of money that she’s now using to help women in tech and raise the UK’s digital prowess. I asked Martha about her greatest personal challenge: recovering from a car accident in 2004 while she was vacationing in Morocco; she broke 28 bones, suffered a stroke, and has endured 28 surgeries. She still suffers from those injuries but she is so positively full of life, and as she told us, she doesn’t let her disability be an excuse. She tells herself constantly: “Always think yes before you think no.” And she urged the MPW to do the same.  Nina: I loved everything about Martha Lane Fox, and now I understand why she is such a sensation in the UK. So many of these women we brought together are passionate about empowering other women. Cindy Gallop, for instance, may bring shock value to the stage—but on a fundamental level, she’s what Fortune MPW stands for: She thinks outside the box, plows new ground, goes where others are too timid to go.  Pattie: You’re right. This former ad industry exec is struggling to raise money to build “the Kahn Academy of sex ed,” as she calls her endeavor. Her startup, MakeLoveNotPorn, invites people to put videos of themselves having sex online, for all the world to see. She makes a strong argument that her purpose, besides making money, is to empower and improve lives.
The leaders at Fortune's MPW International Summit in London say the best way to reach the top is to break rules and ignore critics.