"We all need our best friends. Best friends share good and bad times. We tell our close friends our secrets. But what about casual friends? They are the friends we see only now and then. They are our classmates, the customers at the cafe or the neighbor walking his dogs. Research shows that the more casual friends we have, the better our lives would be. First, casual friends make us happy. We feel like we are not alone. Second, they connect us to other groups of people. Finally, they even introduce us to a variety of new ideas. Our best friends often think like us but they may have different ideas."
The main idea from the passage is ...
