As far as the comfort level goes - it just takes some time. I used to be one of those "gotta go faster" types, and when I decided to make the effort to hypermile... it was tough. It was
really uncomfortable driving only 10mph over the limit, not to mention *gasp* driving at the speed limit on the expressway. But after doing this for a few months, I actually found myself more comfortable driving at the speed limit. It is pretty strange, actually. I've been a knucklehead speed demon my whole life (thanks dad!) but since stumbling onto this site, I started changing my evil
ways and watched my gas expense (and stress level) go down, yet somehow I still get to work on time. Now I can completely ignore (ok, almost completely) the knucklehead speed demons in the rear view who are pissed I'm not doing 80. Eh, F 'em, I say.