do your thing. :) and when you run into someone that shallow, move on.
what you have is a very nice quality.
How to you know they think you are flirting, some people are working and they are paid to be nice to you so to speak, like at their place of work. Or if you are at the gym, they might be too nice to say get lost I'm busy. Sometime people get their signals crossed, please ignore me if you thimk I'm wrong.
nhoj1 may have a point. I lived somewhere for a year where people are (apparently) more reserved about talking to strangers. I personally like to have a little company during breaks, so, I talk quite easily to lots of different people, and unfortunately tend to smile a lot naturally. I've sure never been asked out by so many different people in one year, so, yeah, I guess some people just interpret friendliness to be flirting. Thinking back, I think I'd rather be shot than think that all these people thought I was flirting with them. But yeah, maybe it's a combination between the expectations of the people you are around, and your natural behavior.