Complainers usually have a false sense of consensus. They think that everyone feels the way they do and that’s why they are speaking up. They are the hero saying what everyone is thinking. It’s myopic at best but probably well intentioned. They think they are looking out for everyone. The truth is that what delights some enrages others. An invalid complaint is one that doesn’t improve the experience for the entire team. It’s self-serving in that it aims at moving the circumstance closer to their preferences. A valid concern has the best interest of everyone in mind.