A friend is someone at whom I can yell if I'm pissed off, who isn't afraid to grab me by the arm or shake me by the shoulders and tell me I'm wrong about something and someone in whom I can actually confide.
True friends are rare. People betray trust or they leave and don't return. I tend not to trust easily and I'm not an easy person to befriend. Sure, I have quite a few acquaintances, but I prefer to spend my time alone.