Chronic misery is a disease. It takes a toll on the host and it takes a toll on everybody around the host.
Such people have a hard life for themselves. They find some or the other reason to become unhappy about. They become unhappy over things that do not warrant any unhappiness at all. They make a mountain out of a molehill. By the time, the issue is resolved they will find something else to be unhappy about. They thrive on misery. They also create challenges out of nothing so that they have something to be bothered about and something to overpower. As if becoming unhappy is their biggest love, their biggest hobby, their biggest pleasure.
