Sorry but grow some balls You might die tomorrow You are thinking about it too much Zoom out and get some perspective and realise how small and insignificant all of it is in the grand scheme of things your a human and she is a human and you have had enough years on this earth to simply greet a fellow person with a polite hi whats the worst possible outcome? that she wont return the greeting? even if the chances are small, saying something still gives a better chance that she will respond to you, than the zero percent chance if you keep quiet!