Rude SOB's

The agency I work for is located in an office building with about 10 other companies. There are only 2 bathrooms, one of each floor so everyone has to leave their suites to use one. Ok, here's the thing. Everyone in this building seems so rude! I don't know if it's just me, or what. I say hello or hi or how are you to people when I walk past them or see them walking by, I do this even outside of work, I don't know why I just think it's a nice gesture to say hello as you pass someone, especially if when you look right at the person. It seems most people do not agree. Most of the time my hello is met with a stare - like they too good to respond. Every so often I get a hi, or a nod or maybe a smile, but most of the time NOTHING! It is really starting to piss me off! And if I don't say anything, they just stare as I walk by, like the smokers out front, I usually say hello as I walk in and they will sometimes give me a hello back, but if I decide to wait and see if they speak to me, they don't. I don't know why I find this odd, especially in today's world but it bothers me. I think people should speak to each other in passing, especially in an office building when we see each other everyday. These people are such snobs!!!