We watch as Harold seemingly unexplainably remains obsessed with death and acts of violence that shock people witnessing him do them. When he meets Maude, a 79-year-old woman who believes 80 is the right age to die, he finds someone who shares his carefree confrontational view of the world. She is a woman who teaches him to live fully and in doing so we see him express himself deeply to her. We learn that he's become obsessed with death after witnessing his mother faint after she was wrongly told the news that her son (Harold) had died.
This bond leads their friendship into romance and the pair eventually marry. But Maude takes sleeping pills and dies the next day. We see from this the contrast of a life given to tormenting people in order to elicit a response to one where death is the point in Maude. She teaches Harold that death is not to be toyed with, rather life is to live so that when one's time comes their life has been lived fully.
This is the point of Harold not going off the cliff in his car, but instead remaining to face his life. He no longer simply uses morbidity to find his way to meaning. Perhaps he is on the road to find a way, his own way in life that is bigger than anything he'd ever imagined. All of this is due to the journey he's taken. Without Maude,would he have gotten out of the car? It's hard to say, but life is meant to propel us forward no matter the obstacles - never to make us desire death, but instead to cause us to yearn to discover the power of living life to the fullest.
