It's just a habit you've permitted yourself to indulge. Give yourself a 5-count to start down after you take the bar out of the rack on all your warmups and work sets to teach yourself not to.
I tried google searching for a little while and didn't find a topic related to this question, so here it goes:
When I'm setting up to squat, more often then not I end up doing what could be called a jig while getting my feet into position. Under heavy weights this seems to be a good way to waste energy. I've been squatting as described by BBT for a bit over a year now and this is one of the last issues to iron out with my squat. Is it as simple as practicing consistency while unracking? Thought perhaps you may have a better way to address this little issue.
It's just a habit you've permitted yourself to indulge. Give yourself a 5-count to start down after you take the bar out of the rack on all your warmups and work sets to teach yourself not to.
I think you are right about wasting energy under a heavy weight. I have taken to carefully spotting my stance before unracking the bar. I lift in my garage, and so there are a couple of chalky footprints in the right spots now, but I have a couple of landmarks on the floor for setting up, one of which is a handy piece of exposed aggregate right where my left big toe goes. At any rate, once the stance is set, I try to walk the bar back with fairly wide steps, so I don't have to step out as far to get back to squat stance width. Proper stance width freshly impressed on my wandering mind just moments prior, I slide the dawgs back out, and get the shit done.