We tend to assume that things should be excellent and that that's normality. If it's good, it's good and it no longer needs our attention. That which needs improvement does.
But yeah, why not ask? He will give you his opinion, probably won't bite your head off. :p He's there to help you and teach you anyway, it's his job. Don't let his stony demeanor or reputation spook you out of a good learning experience. And I think he should be able to give more than a nod and a "good" to his students anyway...it sounds like he's terrorising you, but it's possible that he's entirely unaware of it and that this has been perpetuated by generations of meek students.