Like a nasty cold, pessimism is contagious. Although you might take notice of someone who is exceptionally negative, the complainer has become so identified with this behavior that they have no idea how often it is occurring.
That moment where you say “enough is enough”. That split second when you wake up. It could happen at 26 while sitting in a cubicle, when you realize that you’ve been watching cat videos to kill the time for over four years now.