I know from experience that somehow there is a basic hospitality about me, that emanates from me, that causes some men to construe it as interest, and half the time (or more than half) I don't even realize I'm doing it, and yet after the problem ensues, I start questioning whether I should have tried harder not to cause the problem (I hate blaming myself). I also seethe with rage at the fact that no one seems to have ever taught these men that women can look friendly without the slightest intent of something else.
For example (and this is strictly hypothetical, not based on a true story), I could say in front of a man "Gosh darn it I had such a terrible day today" and put my face in my hands, and yet say the same thing in front of another man and that man may interpret it as an invitation to come over and touch me inappropriately. (Well, in reality I'm not going to do this but I'm just exaggerating to prove a point)
I used to be like this to everyone. But with men I'm now abrupt, curt, keep it business and professional I don't smile or entertain conversation with them for too long. It's really hard to do because you have to constantly be aware to do so when you are interacting with them.. and it's probably not something you're used to. The thing with American men is that they are ridiculously touchy feely with women, it's actually alarming. I asked them not to touch me because it's not considered appropriate in my culture to touch strangers. If they try to go in for a hug, I step back with my arms folded and offer a fist bump. American women never feel the need to randomly touch me or hug me. Women only going for a hug once we've hung out a few time and we're comfortable with each other.