It's the same way with running a long distance race, or working in an office... in every day life. You work with people, and you are all part of a team. Should one individual mess up, the whole team is messed up. Every individual counts, and in order to become the best, you have to make sure that each individual is in their top shape and ready to work their hardest.
Today, I played wallyball with my sister and friends, and for 3 straight hours, we played... and I didn't lose a single game. Part of it was because we got lucky, but on most of them, because of the teamwork that my team had, we were able to out-hustle the opponent and win. Now it's a good thing that I'm rather athletic, and the same for my sister, but it was the teamwork that really pulled everything together. With good teamwork, you can do so much, and if that teamwork didn't exist, then it would be more or less chaotic and the team would be a group of individuals with their own specific goals and it wouldn't work nearly as well. Working together, it's not a matter of 10+10, but rather 10X10, improving the amount of output.
Teamwork is what brings people together. Teamwork is what gives us good results. Without teamwork, we won't be able to excel as well, able to produce as much. It is teamwork that helps each individual work together as efficiently as possible.