Hi @26burketta 
Keep in mind that Canvas is a Learning Management System, and it's primary purpose is to provide tools for teaching and learning. And while social activities can be very useful learning tools, they are really not meant to support private conversations between students. And since, as you stated, students might sometimes say "bad things" (why would you want to do that?) and those might be very hurtful to others or be used as a way to cheat on tests or any number of other poor choices; Canvas provides teachers and administrators the ability to review any and all conversations using any of the Canvas Communication tools.
But, in answer to your question, Canvas has many tools you can use to talk to your classmates. And really, you can say anything you want when communicating through Canvas. I can only hope you also understand that everything you do in Canvas is recorded - everything! And, for the most part, this is a good thing. That being said, almost all of the Canvas communication tools are meant for conversations with the members of a single class. The only real exception are the global announcements. If you want to use the Canvas Inbox to talk to friends in your class, this guide will help https://community.canvaslms.com/docs/DOC-10574-4212710325
From my perspective, what you are asking for is what telephones were made for. If a person is your friend ask for their phone number, look them up in Instagram or any of the other 65+ Social Networking Sites.Then, while in Canvas, focus on your school work.
Just sayin'
Kelley
