I've got another vote right here for "fear."
Especially for someone like me - who was raised "in" - it is overwhelmingly frightening to have to think for yourself. I had no practice doing any such thing, no experience being solely responsible for the consequences and implications of my decisions (especially when it came to religious beliefs - someone in New York understood it all, so I didn't have to). Since I thought my identity as a JW was the most reasonable and noble thing about me, I had no confidence in my intelligence and perception of reality once I left. I've dealt with strong inclinations to return because being a fully-functioning adult is hard. When you've had no preparation and are late doing the work of self-actualization that you should have done decades ago as a teenager, any appearance of stability and safety is tempting. As dysfunctional as my life was as a JW, it was familiar, contained, predictable and programmed. It was what I'd known all my life.
It's a challenge to stand up to the feeling that you aren't safe when part of the reason for leaving the Org is because it is so unsafe psychologically, spiritually, and emotionally. To step out and find that there's no warm, cushy comfort zone to rub up against anymore can create feelings close to hopelessness. There's confusion about what to put in the place of the Org when you have a raw, gaping hole in your soul. Honestly, at one point I was looking for another high-control group/cult to join because being self-sufficient was as painful as going without food and water.
Those who leave have to literally burn new pathways into their brains. In the meantime, we have to override those automatic behaviors that make up bad habits - or wait for them to fade.
I found support before I left - online, in person, and via mental health professionals. I continue to look for support, continually challenge my thinking, and try to be patient as I learn mature social skills. I've also learned that if I wait out the yearning to go back, it eventually goes away. And those feelings don't come as often or as intensely as they once did. Even if I went back full-force, things would never be as they were. I'm much happier about the potential for my life now that I'm "out", whereas my life among the JWs promised nothing but more F.O.G. (fear, obligation, and guilt - "Emotional Blackmail").
As Robert Fulghum once said, "The examined life is no picnic."