Among the many memorable lines written by the Bard of Avon (Stratford-upon-Avon, the town in Warwickshire county, England, not the cosmetics and personal care company), few are more-often quoted than what the beautiful young Juliet Capulet says to her beloved Romeo as she bids him good night: “Parting is such sweet sorrow.”

So it is, after 60 contributions to Forbes’ marketplace of ideas, that I say farewell. I’m assuming “emeritus” status at Boston Consulting Group and plan to focus my time and energy on my teaching duties at Harvard Kennedy School and Dartmouth’s Tuck School of Business.

It probably goes without saying, but I’ll say it anyway, leadership—my wheelhouse these past 30 months—has never been more important.

In these columns  I’ve discussed a lot of different themes: how leaders can make better use of data, artificial intelligence and technology; their role as communicators; managing change at a time when management itself is changing; how to make their organizations more “agile;” the need to “champion,” not just mentor, the next generation of managers and leaders; empowering and helping teams; creating the proper culture; prioritizing diversity and inclusion; getting more from (and giving more to) Millennials; the pros and cons of remote work, and even planning for a satisfying retirement.

I profiled some world-class business leaders, such as Indra Nooyi and Satya Nadella, immigrants who rose to the top ranks of global business, and I offered some fatherly advice to would-be leaders of the future as they graduate from college.

For more on these and similar issues, I encourage you to follow the new column by Deborah Lovich, my friend and colleague and one of BCG’s best and brightest. Her insightful thinking on the future of work and many of the other issues I’ve touched upon—and some I didn’t—is unparalleled.

With everything I’ve thrown your way over these many months you might think that leadership itself is secondary. Put enough of the individual pieces together properly, like a jig-saw puzzle, and your organization will thrive.

If that’s the impression I’ve given, I’ve failed.

The minutiae are important; but don’t get caught up in the weeds. Leadership is the critical secret ingredient—the powerful adhesive that holds everything together. Bad leadership destroys cohesion; it destroys value; it’s been known to destroy companies.

Good leadership is a creative force.

I want to finish by repeating the same few words I offer my students at the end of each semester: Be Kind; Change the World.

There are few times in modern history when the world was more in need of kindness and change. This is among the huge responsibilities that comes with leadership: to be kind and help change the world.

That’s why we need great leaders.