You go through the "suck" with each other.
You cheer each other on.
You encourage each other.
You keep each other accountable.
You see each other reach personal records.
You give your best effort because of each other.
You have fun with each other.
These are all benefits of group training. There is a reason why CrossFit became so popular. It wasn't just because of the style of workouts or the overall methodology.
The power of CrossFit was realized when people started to do it together. There was nothing like it in the early 2000's and to this day, there still is not. There are many programs that try to replicate the group model of CrossFit, but at the end of the day, it is very difficult to replicate.
I highly encourage you to get involved with your community when you're in the gym. Get to know each other. Say "Hi" to each other (our first gym rule). Cheer each other on. Exchange numbers and hold each other accountable by texting each other when you plan on going to the gym. Get outside the gym and sign up for events with each other to express all the great fitness y'all gained together.
Enjoy your community. Surround yourself with the types of people we have in our community because these are the types of people who help us become the greatest version of ourselves.