Nomar always had to throw off-balance, while running and jumping. You can see his style on display when throwing the ceremonial first pitch at Fenway last year.
In an interview (can't find the reference, sorry) he said he always had to throw this frenzied manner, even for an easy grounder where he'd normally have time to collect himself. If he paused too long to think about it, the throw would come off badly, he said.
I always thought this was a psychological issue -- dubbed "Steve Sax Syndrome" by some.
But on those slow holiday ED shifts, I think it's just a good habit. When you're used to functioning well at a fast pace, slowing it down doesn't necessarily make you any better. Our ED's workflows, our data collection, and our decision-making, all all calibrated to work at a certain speed. Slowing it down sometimes lets us unearth a valuable piece of information -- but more often, it just pushes the signal-to-noise ratio toward more noise.
And hey, it's not like Nomar's quirk kept him from having a stellar career.