In the well oiled machine that is a crew of a spaceship, you either get friendly or have the ship explode and be hurdled into the cold nothingness.

Have your friends follow you into a battlefield where the PTSD can be very real. Being hunted down as you huddle in a house hugging eachother in a dark stormy night makes for good friendship exercise.

I can't think of anything you can't do here. Not only is the fun limited to you, but also to other people who are handy with making mods for the game. Play with a good friend, and eye the workshop!