That inexplicable feeling of utter weightlessness and suspension of all faculties when an unexpected encounter happens. Never mind that there is no relationship or even friendship to speak of. That feeling that breathing has suddenly become a conscious activity, and the flutters that erupt in the chest. Never mind that we haven't spoken in months. The split second of utter certainty that someone is meant for you, no matter what their/your relationship status happens to be - before the brain kicks in and tells you to stop being a fool. The power of someone to unsettle you so much...