What makes friendship so great is the same thing that makes it so dangerous. With friends, we drop our guards. We’re most open to influence from others when we’re with people who accept us the way real friends do. Acceptance leads to influence. And it can work for us—or against us. Some of the most addictive behaviors imaginable are those that people began as pastimes with friends. Our friends greatly influence the direction and quality of our lives. In fact, they can actually determine the direction and the quality of our lives. Think about it: how much have your friends impacted who you are? Friendships are valuable. But because friendships can also be dangerous, we need guardrails.