What are the cons of peer pressure?

Just because some group of people believe that some particular activity is a good thing to do, does not in any way guarantee that it is. For example, it has often been noted that many people start smoking cigarettes because of peer pressure. Smoking cigarettes is a really bad idea. So in essence, there is the risk that your peers might be very foolish. It is always better to figure things our for yourself, rather than to depend upon others to tell you what you should think or do.