People here do not like eye contact

I am 21 years old and on a good day at work can be found wearing an un-tucked polo shirt and some khaki pants. On a bad day I am wearing a t-shirt with toothpaste stains and jeans with holes around the back-pockets (why do holes form here?). I am tall and skinny with a scruff of unkempt curly hair. I am not, by any standards, an intimidating looking person. Certainly in a professional corporate setting there would be no reason to look towards the floor, or the wall, or back and forth repeatedly between the two in some kind of frightened attempt to avoid eye contact, when passing the likes of me in the hallway. And yet this is exactly what I see.

I understand that these are not normal people, that they have PhD's in things like Physics and Materials Science and that for these they have sacrificed some of the more sophisticated social skills such as knowing when to draw someone a map and when to simply say "the bathroom is around the corner," but I thought that a head nod or simple "hello" when passing a fellow co-worker would be within everyone heres ability.

I was mistaken.