I normally see "heady" used to describe a pleasant scent, and I normally see it when I am reading books. I rarely hear it out loud. Perhaps if I worked in a perfume or candke store, I would encounter it more. :)
I have never heard "heady" or "headiness" used any other way. For anger or a short temper, I see and hear "bullheaded" used often.
For reference, I'm in the USA.