I bought a lovely satin-chrome HP just a few weeks ago, and came home with a bloody left thumb... ouch!
Changed my grip, and no more problem. Fortunately, when I pick up this weapon, I adopt the changed grip almost automatically...
I figure this would be a major problem for someone with larger hands though: mine aren't particularly big.
A hammer bob, or one of those nice rounded-spur hammers, is on my horizon, though!