Back on topic, that's one of the best things I've read here in ages keepitreal. I felt exactly the same after I left QR, I didn't realize how much of a zombie I was until a couple weeks after I left.
The subtle high-level mental stuff like your imagination, coming up with new games for the kids, enjoying reading a book, your basic attention span etc, when you're in the system it's all gone under the perpetual cotton wool of fatigue and you don't even realize what you're missing.
We only have 80ish years to spend on this earth, the question is how many of them are you going to spend in that horrible mental state and that horrible working environment?