I would guess you've been through it many times or are lucky enough to have a great intuition with this. I've personally not been so lucky.
I can say that in my experience reading Four Steps or The Lean Startup and actually doing a startup are completely different things. I thought I had the whole lean startup thing down, but I've messed up so many times. And it's not a case of "now I've learned my lesson" either. I've had great experiences with sticking to lean, and then afterwards I've slipped up again. For me it seems to be a case of waves of being good, and not so good. Over time I'm definitely getting better.
I can say that in my experience reading Four Steps or The Lean Startup and actually doing a startup are completely different things. I thought I had the whole lean startup thing down, but I've messed up so many times. And it's not a case of "now I've learned my lesson" either. I've had great experiences with sticking to lean, and then afterwards I've slipped up again. For me it seems to be a case of waves of being good, and not so good. Over time I'm definitely getting better.