Girls, what is your reaction when a guy approaches you?

Wording this is really tricky. I feel like I'm going to offend someone. Basically, ladies, I'm wondering what you guys think when you're approached by a guy who possibly wants do date you. The reason I'm curious is because of how I feel when I approach a girl. I tend to think that if I approach a girl, that, without even asking her out, she'll just think that I'm trying to get into her pants. Is that how you react? If not, how do you react?