This expression suggests that the writer's reflections or thoughts, prompted by procrastination, have evoked a strong emotional or personal response. In other words, the writer's contemplation on the topic, likely related to procrastination, has resonated deeply or struck a chord, perhaps causing the writer to feel a heightened level of self-awareness or emotional impact. The phrase "hit a nerve" is often used to convey a reaction or response that is intense and personal.

Hahahaha ... That sentence had quite a sense of humor in it! My interpretation is that the author's idle thinking triggers a certain emotion.