In “The Anxiety Optimization” (Season 8 Episode 13), Dr. Sheldon Cooper has an epiphany after struggling to make a breakthrough in his newly chosen field of Dark Matter.
Sheldon: “The reason I may not be progressing in my research is I’ve created too pleasant an environment for myself. According to a classic psychological study by Yerkes and Dobson, in order to maximize performance, one must create a state of productive anxiety. So, I like to ask you all to do something for me. Keep me on my toes. Throw me off my game. And essentially, go out of your way to make my life miserable.”
Gang: “What’s in it for us? (slight pause) Okay we’ll do it!” Hilarity ensues as his friends torment him for sport.