Resistance seems to come from outside ourselves. We locate it in spouses, jobs, bosses, kids. "Peripheral opponents," as Pat Riley used to say when he coached the Los Angeles Lakers. Resistance is not a peripheral opponent. Resistance arises from within. It is self-generated and self-perpetuated. Resistance is the enemy within.
Steven Pressfield, in The War of Art (p. 8)
'Resistance,' in Pressfield's terms, is that thing that holds us back from getting on and working at creative work. Procrastination is one of its most successful manifestations.