Ready for the take
No longer necessary, but some things never change. A conventional but still popular tool for keeping track of the number of takes, the clapperboard is like a ritual in the film making industry.
The most important part of filming is the ground work, the detailing and cloaking it around yourself so its a part of you. Also, its a not so small matter of millions of bucks and the even more valuable integrity you have earned in years.