I don’t remember the exact day I first met most of my friends, but with Warren Buffett I do. It was 25 years ago today: July 5, 1991.

The date stands out in my mind so clearly because it marked the beginning of a new and unexpected friendship for Melinda and me—one that has changed our lives for the better in every imaginable way.

Warren has helped us do two things that are impossible to overdo in one lifetime: learn more and laugh more.

Over the last quarter-century of our friendship, we’ve done a lot of both.

If you can read this, you probably have access to affordable and reliable electricity all day, every day. 1.4 billion people around the world don’t.

We need to address the impacts of climate change by investing in innovations that will help power the world with carbon-free energy. At the same time, we must find ways to deliver affordable energy to people who don’t have access to electricity today so they can live healthier lives, build stronger communities, and find a path out of poverty.

In my travels, I’ve seen how lacking access to energy has impacted people’s lives, sometimes in surprising ways. But I’ve also seen how innovative and resourceful people can be in the toughest circumstances.