They're not actually listed as unhappy. And this isn't about specific players, it's about how the anger system works. All the threads in players are player-specific.
My captain got mad at me for lack of discipline some time ago. Then one of my players got a red card, I fined them, and I got a note saying that my captain's personal issues with me were now resolved. If I go into "personal" on their profile, there's no mention of personal issues. However, when...