Be Open-Minded. Nothing good will ever take place if we only listen to our own opinions. In the movie, Grug only wanted everybody else to do the things he suggested. But at the end, he came to realize that he also need other people's opinions. Respect other people's voice even if they are not the same with our own. The world is a huge place and we will always meet people who think different thoughts from our own. But just because we think different thoughts doesn't mean that we shouldn't be friends.
Follow your dreams. Never ever let fear get in the way of our dreams. We all have things that scare us. Like in Grug's case, the fear of the unknown and the new sometimes scare us. But we have to believe that there is something greater than fear. We have to believe that our dreams weigh more than our fear. Follow your dreams. Don't spend your life living on what-ifs. Instead, go and do something about them. It doesn't have to be a grand beginning. What matters is that you started.
Don't take the risk, just take the chance.