Because there's a glut of people who are impossible to please. You an hear it in chats with others and in other's conversations, whether about movies, food, relationships, weather, jobs, family or whatever.
People tend to say, "this was cool but…" or "I like everything except…" That position can sometimes be useful as a way to improve things, but more often it perpetuates a sense of longing, that nothing is ever good enough. This leads in the short term to dissatisfaction with our lives and relationships and with others and what they do. In the long term it's the root of bitterness.
People rarely say what utterly delights them, with no qualifiers. Better to just be pissed off and angry and make everyone else the target of your anger.