Actually no, most people do not have mood swings. Most people experience emotions and physiological effects as a direct response to their present situation, and then recuperate fairly quickly.

People with mood disorders experience emotions and physiological effects that are randomly manifested regardless of the situation, and may also be launched into severe mood episodes by outside stimuli, as well. Then these emotions and physiological effects may last weeks or even months, compared to a neurotypical who will recover within minutes, hours or days depending on the severity of a situation.