Just got done reading Richard Dawkins' fabulous new book on evolution, "The Greatest Show on Earth" (which I'll review anon), and discovered that when we hominids began walking upright our nasal passages in our cheeks couldn't drain anymore.
There are two drain holes at the top of the passages, so while we're standing, our sinuses fill up like thirsty reservoirs. Ever get that heavy head feeling during sinus season? Yep, that's why. Well, as you can imagine, the apes don't have this issue because they still get around pretty much on all fours (and it's also why liberals don't get sinus infections).
After reading this article, I got to thinking, "How can I solve this issue?" Then Eureka!
So, if you see a guy at the mall bent over 90% with a Rube Goldberg-style vision apparatus attached to his eyes and head so he can see straight ahead, that'll be me. Just don't expect me to stand up and shake hands. I might spew.