The secret to mastering the nafs

After over 15 years of coaching, I'm going to let you in on a secret.  There is something that happens in almost every single coaching session, at the moment the client has a breakthrough:  They drop their nafs.  For real. "Insight is when the ego collapses over a particular subject", as mentioned in the book, 'Inside the Soul of Islam'.    What does that look like in real-life?