"Working with a lot of people at the same time is a task. I really like making stuff and getting stuff done. One of the things I really liked about Facebook was that I could always move so quickly. I wrote the original application in, like, nine days at the end of January"

Mark Zuckerberg is revealing his appreciation for the speed and performance of working at Facebook. He is saying that working with a lot of individuals at the very same time can be an uphill struggle, however he delights in the difficulty of getting things done. He is especially impressed with the speed at which he had the ability to write the original Facebook application in just nine days. This speaks to the effectiveness of the work environment at Facebook, and the capability of its workers to move quickly and get things done. It is clear that Mark Zuckerberg enjoyed his time at Facebook and appreciated the speed and performance of the workplace.