I think the thought process is something like this: " Wow, this girl seems to really like me. It can only go downhill from here. I'll probably say something stupid and fukk it up. If she didn't like me I could just say anything with nothing to lose. Dam this is too much pressure.....I'm out
"
Here is another possibility: "Hey that girl over there is smiling at me. I'm used to approaching girls who don't even know I exist and trying to convince them to like me. I don't even know where to begin with this one. Is that a friendly smile or does she want to jump my bones. What if it ends up being a friendly smile...... I'll feel really stupid trying to come on to her."
OR: "O sh!t, she just winked at me. I'm not ready for this. I didn't shave or iron my shirt. Dam I got no gum...... what if I have bad breath. Fukk she caught me off guard. Should I just go for it.....o man she's leaving........dam next time..........next time I'll be ready"
LOL I thik i've had all of these at some point or another. I think that's why so many guys preach the word CONFIDENCE when they talk about being good with girls. Confidence in yourself and that the girl will really like you. If you don't have that you can't even get into the game. Of course confidence w/o some social skills is useless but you cant develop your social skills w/o the confidence to talk to people.