Difference between flirting & being nice?

United States
@maezee (12745)
December 31, 2010 11:47am CST
I feel like I have a hard time telling the difference between when a person is flirting versus just being nice. One example is just that I was at work yesterday and I guess the girl I was working with thought this guy was flirting with me. And I was thinking..No! He wasn't. He just seemed like he was being very nice and friendly. I am usually so good at reading people, but in this case, I really can't seem to. How can you tell the difference between flirting and just being nice/friendly? Where is the line to be drawn?