The Balls in Flirting

Hmm, girls. These bring back memory to a discussion, which I have with my colleagues earlier. Sometime ago, I was taking LRT (Light Rail Transit) to Taman Bahagia to meet my sis. While on the LRT, there are two pretty looking girls sitting directly in front of me, which are attractive enough to make me uncomfortable. At first, I was looking directly at them, but I can't really keep staring at them through out the journey, as it would be rude. So, I would have to pretend to look else where, up, down, left, legs, behind them, whatever. But I do notice they are doing the same thing to avoid direct eye contact as well. It is not quite common around here to directly approach a stranger for conversation, or I am just giving myself excuse to be shy and cowardly. I am still more comfortable meeting someone from someone I know. Kenny (one of my colleague) said I should just go ahead and give it a shot, there is nothing to loose except rejection. Am I afraid of rejection? Or is it just something I am not comfortable with. Guess it is one of those Comfort Zone and Artificial Boundary thingy again. Probably I need help from SIRC Guide to Flirting :)