Girls Smiling

I hate it when a girl smiles at me. I never know why she is smiling. Is she smiling because she is a friendly person? She simply likes to smile? She likes to smile at people? That's great. Girls should be friendly. Or is she smiling at me specifically? Does she have some other reason for smiling? Did I do something stupid? Something amusing? It's not unlikely. Or is she smiling because she is interested in me? I know, its hard to believe. But there is that chance isn't there? What is a smile? It's a way of communicating through body language... what? Satisfaction, comfort, gladness, politeness, willingness, irony, humor... A smile is not enough to go on! So what does it mean when a girl smiles at me? Does she like me? Is she smiling for no reason? Am I overanalyzing?