When I received my 7D (mk1) all that time ago now, I spent the first week just playing around with it each evening without a memory card in the slot so that I could really learn everything about it. That really paid off, because when I finally put a card in, I knew the camera so well and had already customized it to suit how I wanted to use it.
Once I got my 5D mk111 and reprogramed the DOF button to select Al Servo instead (finger falls into place perfectly), I wished that the 7D also had a button there for quick changes to moving targets from Single.
I use my 3 custom settings all the time as it is, but often want that Al Servo even faster than I can flick that dial and think the 7D mk11 has a button there now and like the idea of the new model just for that alone.