Game production is like a Roller Coaster:

"Game production is like a Roller Coaster"

Think of the Game Design Document (GDD) as the shoulder harness, the Technical Design Document (TDD) the wheel clamps, your Team as the colorful car and the steel track as the intimidating Production pipeline!
The first two will keep you fastened in when things start rolling! The third will be around you to support and the last will pitch, yaw and loop you all over the place! 
Game Development can be quite scary and intimidating but like any good roller coaster, its still an exciting and wild ride! 
It's why we always run to get back in line again!