By most every measure, Southwest Airlines is a tremendous success. Southwest is the largest domestic air carrier in the U.S. and at the end of 2017 it posted its 45th consecutive year of profitability.

So it came as a bit of a surprise that, in an interview posted yesterday, Southwest Airlines chairman and  CEO Gary Kelly revealed the one big mistake that he made in what could only be considered a successful career.

Southwest was founded in Texas in 1971 with just three Boeing 737 aircraft. The company was led for many years by its flamboyant co-founder, Herb Kelleher, who served as chairman and CEO for many years. Gary Kelly took over as CEO in 2004 and chairman in 2008.

In the interview, Gary Kelly reveals that he made one big mistake along the way. Says Kelly:

"I wish that, earlier, I had slowed down a bit. Not meaning that I wish I had worked career was always getting to the next thing. I don't mean getting to the next position, in terms of climbing the ladder. It's just very focused on the future and a to-do list and let's get this done, and we've got to get the next thing done.... I think I would have made fewer mistakes had I been a little bit more measured."

We live in a world that is increasingly volatile, uncertain, complex, and ambiguous, and this means that leaders need to make decisions and act faster than ever before. But, as Gary Kelly points out, it's a mistake to make decisions and to act too fast.

Great leaders always get all the data they need to make important decisions, they obtain the inputs of their key people, and then they take time to thoroughly consider their options. They don't allow analysis paralysis to creep into the process--they act quickly and decisively the moment they have what they need to make the best decision possible.

While Gary Kelly may feel that he didn't always make the best decisions possible, it's clear based on Southwest's tremendous success that he made the best decisions often enough.