You can have friends that are also coworkers, but you cannot have coworkers that are also friends - the “primary” relationship is important, IMO. If the primary reason we’re interacting is that we work together, there’s obviously no reason we can’t be friendly but we are not actually friends.

If your coworker is a coworker first and a friend second, why wouldn’t you pick a raise over them? Why wouldn’t you pick a promotion over them? Why wouldn’t you rather them out for something that negatively affects your job? At that point, it’s just a subjective scale for what you would do for the job and what might screw over your coworker.

People existing in society in good faith. People who just want the world to be a better place to live, and aren’t willing to shove people down below them in order to get an edge.