It's pretty cumbersome being me

I make progress daily in my research, since I'm an extremely clumsy person. More frequently than I'd like to admit, I run into people, sometimes jarring myself so hard that I stumble. Lately, I've begun to not apologize when this happens (even though this faux pas eats me up inside), and I've been met by what can only be described as genuine glares. Some have yelled at me, some have sarcastically cajoled me on my inability to walk in a straight line, but absolutely none have ignored me. 

I seek to continue my blatant lack of grace in Europe, where I expect different reactions. I seek to find the source of this ignorance of personal space. What causes people overseas to be so much less uptight? Granted, to answer this question I'll need to do a lot of inferring and assuming, but it's better to postulate than to give up.