Starting a company with your best friend: It's a proposition so fraught with potential for disaster, there's an entire genre of business advice dedicated to enumerating the pitfalls.

On the other hand, there's Apple, Google, Airbnb, and all the other household-name enterprises that started out as projects between buddies. So clearly it's not always a bad idea.

Claire Mazur and Erica Cerulo have been inseparable since they met as undergraduates at the University of Chicago in 2002. In 2010, they co-founded a boutique fashion e-commerce website called Of a Kind, which put the focus as much on creators as on their products. After five years of steady growth, Mazur and Cerulo sold it to Bed Bath & Beyond, where they've continued to run it.

In their experience, best friends make great co-founders. But even more than that, they assert, female best friends make for great founding teams. The qualities that characterize the strongest friendships between women -- intimacy, vulnerability, supportiveness -- also make for the kinds of professional bonds that enable success in a startup environment where the hours are long, emotions run high, and boundaries barely exist. Yet those qualities are badly undervalued in corporate America, where leadership is synonymous with individualism and steely self-containment.

That's the idea behind their smart new book, Work Wife, which explores the phenomenon of friendship in business through their story and the stories of other successful partnerships, from the co-founders of Food52 to the Olympic beach volleyball tandem of Kerri Walsh Jennings and Misty May-Treanor. In a phone interview, they told me more.

Inc.: What's the difference between a high-functioning professional partnership and a work marriage?

Mazur: The difference is that a work marriage really leaves the personal in, and it takes for granted that someone has a personal life, and that it is necessarily tied to their professional life. It's not just saying, we are just here for each other in this work context, but to say, we're here for each other fully, and we are considering the forces that happen outside of the office when we interact with each other.

The term "work wife" has a somewhat sexist origin. Tell me about that.

Cerulo: The term came into existence just nine years after women's suffrage passed. In its original form, it basically referred to a man's high-functioning secretary; someone who was his wife, but at work. So we have reclaimed it -- and women more broadly have reclaimed it.

You're pretty careful to avoid gender-essentialist claims -- "Women are like this, and guys are like this" -- but the core of your argument is that there's something in the way women relate to each other that carries over into successful professional partnerships. What are you saying and what aren't you saying?

Mazur: Women's friendships are often defined by this sense of emotional intimacy and transparency and vulnerability, and we necessarily bring those qualities into our work friendships as well. As it turns out, those qualities are really beneficial in an office environment. And that is distinct from what we sort of think of as the traditional corporate culture, because men have defined what corporate culture has meant for however many years. But as you get more women in leadership positions, and you see them collaborating with one another, our notion of corporate culture starts to evolve.

For those of us who can't enjoy the full benefits of female friendship on account of being dudes, what can we learn from the work wife phenomenon?

Mazur: One thing we hope all people take from this is that bringing the personal into the workplace shouldn't be this scary thing. Obviously, it shouldn't be a free-for-all, but if something is affecting you, in a big way, outside of your workday -- if you're dealing with a sick child or if you're having issues with family, and they're affecting your work, or your ability to focus, or your levels of anxiety -- it's helpful for the people working closely with you to understand those things because it'll help them be more supportive of you. Maybe you get fired up in a meeting about something that seems like really small potatoes, but if people have this context, like, "Oh, you've got a lot of shit on your plate right now, and maybe that's why you blew up," that just helps everybody function better.

Is there a generational component to this? There's this idea that Millennial workers want to bring more of themselves to work than maybe previous generations thought was appropriate.

Cerulo: I think a lot of Millennial workers have come of age in an era when their emails have always been on their phones and their bosses have often texted them, and they've been Facebook friends with co-workers. There is just a certain fluidity they expect as a result of that.

One of the most interesting ideas you raise in your book is the concept of "peer promotion." Basically, we've all had this experience of being on teams or in partnerships that helped us be uniquely effective at our jobs, only to have individuals be hired or promoted out of that group. Can you talk a little bit about that?

Mazur: This idea became really obvious to us when we sold our company to Bed Bath & Beyond. We knew we would suddenly have this very different dynamic -- we would have a boss, and we would be reporting to somebody, and there was a lot of uncertainty on our parts about what that would mean for our partnership. You just don't see people respected as -- for lack of a better term -- "partners" within a traditional corporate environment. There are very few places where that is a custom, and really the only one I can think of is in the advertising world, where art directors and copywriters pair up, and tend to sort of move around together.

We were really concerned: Would they try to split us up? Would we end up pitted against each other, or competing with each other somehow? We were very, very fortunate that we have been respected as a partnership, and treated as sort of a single unit in a way, and I think that's in part because Bed Bath & Beyond was also started by two best friends who are very much equal as co-founders, co-CEOs, and now co-executive chairmen. We found ourselves a sort of unique circumstance. But you don't see people getting raises as a twosome in a typical corporate environment, you don't see them getting promoted as a twosome or a threesome. Hopefully, we'll start to see more of that.

Cerulo: Every job interview you've ever walked into in your life, the company wants to know you prioritize teamwork and wants you to demonstrate how you've worked on a team. The idea of collaboration in a workplace is so core, yet it's not something that's actually valued in the way the company is run.

Is there a basis for this idea that going into business with your best friend can be a terrible idea sometimes? You heard a lot of success stories, but did you hear horror stories, too?

Mazur: There are certain types of friendships that work well in a business environment. Not all do, and one of the things that is absolutely key when considering if a friend would make a good business partner is where your standards are. If you guys both have really high standards and are willing to be accountable to each other's high standards, then it can work; but if you guys have different working standards and wouldn't be willing to respect the other person's, or would be disappointed if the other person didn't meet yours, then that's when it doesn't.

So on the question of similarity versus complementarity, the really important way to be similar is to have the same standards?

Mazur: Yes and no. Erica and I both have really high standards, but we have high standards about different things. We hold each other accountable to different standards, and we're both better off for it. So Erica's prickliness about grammar means that I become prickly about grammar in a way that I wouldn't be if she wasn't around. And I have certain things that she probably wouldn't have paid as much attention to before, but now that we're partners, and she's representing me when she goes out into the world, she's thinking about these things. That's one way in which partnership makes you better.

One knock on the work wife idea is that, in 2019, we're all bringing way too much work into our personal lives. We're sending emails in bed; we're checking Slack when we're out to dinner. Is the work wife phenomenon just one more expression of our inability to maintain any space for ourselves outside of work?

Cerulo: We would argue that the work wife relationship is a way to bring more life into your work. You're speaking to the fact that there's constant work, that it seems inescapable, that you're getting emails at 11 p.m. while you're trying to watch 20 minutes of TV, right? We can try to turn some of that back and try to reclaim those hours, or we can try to take what is happening in our day-to-day lives, and bring the emotional, the personal, and the lightness and fun of friendship into the workplace. So you don't feel like you're constantly sacrificing.

And just accept the reality that finding this work-life fluidity is more the answer than attempting to seek some balance that you're not going to achieve.