Depends on the type of “workplace” really, but generally, the answer is because work is an unstable capitalist mess and you have no confidence as a worker that you’ll have a job tomorrow, regardless of performance.
You see, your list frames a “failing” of workers to connect, while you’re ignoring the larger system in play. Kind of you walking around Nazi Germany saying, “hey, why is everyone such a frowny bummer? Marching is fun. Okay, so which three snacks would you all take to a desert island?”