From "Where did depression come from?" on
http://www.psychologytoday.com Say something. Anything. If you're on a bus or subway, push yourself to sit next to someone who looks interesting and say something: "Do you think this bus will ever get to its destination before sunrise?" Of course you run the risk of rejection. Even here an evolutionary perspective is helpful. When our ancestors lived in small bands, rejection was painful because there were dire repercussions. Rejection by even one person would be communicated to the whole group. Your status was diminished, your position threatened. In 2003 the repercussions are negligible--although we still react emotionally to rejection as if our existence depended on it.
This is one tip for overcoming depression. It means that a long time ago people lived in small communities and as a result rejections were very serious. In modern times, rejection is not so bad; rejection will not affect our status. We shouldn't be scared of talking to strangers. Our status (which means social position in this example) can't be lowered by rejection from a stranger.