Believing that things will never improve takes no imagination: “I’ll keep losing money. I’ll keep getting fatter. I’ll never find anyone I love. People will continue to kill each other. The planet will keep getting warmer.” But believing things can improve requires thoughtfulness and creativity to envision reasons why and ways how they could get better. Unimaginative people are boring. Creative people are interesting.
Believing that things will never improve relieves yourself of the burden of trying to make them better. It takes no effort to deteriorate. But believing that things can improve necessitates the effort to make it happen: you have to work harder, overcome unpleasantness, challenge yourself. Lazy people are boring. Industrious people are interesting.
Believing that things will never improve murders ambition. If you presume your career is doomed, your love life is doomed, the world is doomed, then you have no reason to set goals, let alone try to achieve them. You give yourself a permanentexcuse to let your dreams whither. But believing that things can improve means believing that nothing prevent you from reaching your objectives other than yourself. Complacent people are boring. Ambitious people are interesting.
Believing that things will never improve makes you whiny, angry, and generally a turd to be around. Turdish people are boring. Pessimists are boring.