The prefrontal cortex is the logical manager of the brain. The amygdala is the primeval alarm system. In a healthy brain, the prefrontal cortex can override the amygdala. If you have to do a boring task, the prefrontal cortex says, "This is boring, but it is not dangerous. Let's do it."
In ADHD, the prefrontal cortex is under-aroused (due to low dopamine and norepinephrine). It lacks the strength to override the alarm system. When you look at an administratively heavy task (like taxes or laundry), the brain calculates the "Cognitive Friction" as too high to cross.
The amygdala interprets this inability to cross the barrier as a failure, generating massive anxiety. It initiates an "Amygdala Hijack," literally shutting off the logical parts of the brain and forcing the body into avoidance behavior (flight). The task becomes neurologically coded as 'pain'.
Furthermore, the relief you feel when you say "I'll do it later" releases a tiny burst of dopamine. The brain learns that *avoiding* the task is rewarding, deeply embedding the procrastination loop into your basal ganglia.
