Reference from "The Outsider" by "A Perfect Circle".
In the game of racquetball, the inside line of the serving box is often refered to as the fault line.
Significantly, a model serve will have the foot of the server connecting with but not overstepping the fault line which would result in a foot fault.
Metaphorically then, instead of crossing a boundry in an act of uncontrolled aggression, hold your passions back just enough to stay in the game while remaining competitive.