When you're unhappy, disappointed, or annoyed about something, you feel a sense of dissatisfaction. Your dissatisfaction with your boring French class might inspire you to switch to beginning Mandarin.
An entire country's dissatisfaction with their government can lead to a new administration being voted in, or in the case of extreme dissatisfaction, a revolution. Your dissatisfaction with the pasta dish you ordered might simply make you ask for a hamburger instead. Dissatisfaction adds the dis-, or "lack of," prefix to satisfaction, which originally referred to "an act by a priest to atone for sin," but came to mean "contentment" by the 14th century.