|1.||mutually assured douchebaggery|
The point at which you and another person get so passive-aggressive to each other that it doesn't matter who started it, because at this point you're both just plain douchebags.
Person A turns down the thermostat. Person B waits for A to leave, turns it back up. Repeat until one has to leave out of frustration. This is the point of mutually assured douchebaggery.