Gym Zombees?

There is a feeling so strange yet gratifying when I work out at the gym. David and I go almost every weeknight and see the same people at the same time. I could differentiate the focused singletons with their iPods and constrained smiles versus the group exercisers that huddle around the same workout machine chatting, laughing and taking turns. As a one-year old newbie to health and fitness, I can't help but wonder what the motives of these other people around me are every time we show up. It feels so strange to have eye contact with any of them and to leave the gym with only a "hello". Is the gym a place just to have surface friends or am I just too timid to go beyond my comfort zone and make new friends? I see these people all the time, but will a conversation be encroaching on their personal time and space? I admit that I am a very shy person and can come across as being a snob. I just don't know what to say usually. I wonder if this will change.