A peculiar feeling of connection with a stranger. Curiosity starts kicking. Hesitation comes to the rescue with the fear of awkward situation in one hand, and the fear of unwelcoming reaction in the other. You restrain yourself from asking. The chance is blown successfully. End of story.
I think we all agree that each and every one of us is different in his/her own way, and this difference has many shapes, and it differs within itself throughout our lifetime. We are meant to be like that after all, we have different personalities, backgrounds, standards, and cultures.