“If you and I agree all the time then only one of us is necessary” I stumbled on this anonymous quote and love it. It neatly encapsulates the necessary tension between two business partners, a boss and her staff or indeed a husband and wife.

The best businesses partnerships I have seen are where two very different people have come together. Maybe one has a marketing background the other financial, or a people person and a strategist. The point is that they complement each other, one is strong where the other is weak, and yes of course they argue.  But it’s good arguing, it gets a better result.

A great example of this is in the movie The September Issue. For most of the 90 minute film Vogue Editor –In-Chief Anna Wintour is sparring with Vogue’s Creative Director Grace Coddington. The tension between Coddington’s artistic talent and Wintour’s business brain is palpable, no more so than when Coddington has sweat blood and tears to produce a photo shoot which Wintour proceeds to throw out. Even just looking at them you can see he two women are poles apart (Coddington is sensible shoes and no make-up, Wintour is perfectly put together) but as a combination they are so powerful that they have sat at the top of the $300 billion fashion industry for 20 years.

One of the reasons that I like the example of Wintour and Coddington so much is that they are women. In my experience, and I am prepared to be vociferously challenged on this, women are far more likely to start a business with someone that they are very similar too, than someone who is their opposite.  I few years ago I spent some time with a business run by two friends, Penny and Amanda. They were both great ideas people but absolutely hopeless at execution. The business was on its last legs when Penny decided to exit it. She sold her share to Sarah, a women Amanda disparagingly described as “so not me”.  But the unlikely combination turned out to be perfect; Sarah wasn’t going to set the world alight with her ideas but boy, she was good at getting things done.

So if you are in business with a partner, thinking of starting a business with a friend or working closely with an employee ask yourself “do we agree all the time?” And if the answer is yes, it could be time for one of you to go.