When you are doing things on your own you learn more, like if you have an assignment that you need to get the answers from the book you will most likely read most if not all of the book and get more information needed than if you have a whole group telling you the answers. In our History class, we have president packets and you have to look up some of the facts. Most of the facts that you see are completely new and some are pretty funny. If you have a whole group, again you will get stuff from them, you could also be more creative by yourself and thinking of your own ways to do things.
Reason 2, you will get to do what you want to do. In the book The Wave, they had to go to a rally and if you were a wave member and you were not their you were pretty much not a part of the Wave. on page 58 Ben Ross has a poster of the wave in the back of the class. You will always have people telling you what to do, and where to go. You would not be able to be friends that are not a part of your group and if you are they will kick you out of doing worse and hurt