Many people don't understand the entirety of the story of St. Patrick, or why he became a saint in the eyes of the Catholic Church.
The story that most people know about St Patrick is that he was credited with driving all of the snakes on the island of Ireland out through the power of prayer alone. However, many people don't even realize that Saint Patrick was neither named Patrick at his birth, nor was he born in Ireland.
He was born in Britain, and named Maewyn Succat, though the exact date and location of his birth has been disputed. When he was a teenager, he was kidnapped by a group of pagan Vikings and brought to the Island of Ireland to be sold off as a laboring slave.
It wasn't until after he escaped captivity and returned to Britain that he decided to pursue his faith and begin working as a missionary, which brought him back to Ireland at the age of 22. He would pursue converts from paganism by using the 3-leafed clover as a way of explaining the Christian Holy Trinity (Father, Son, and Holy Ghost) to non-believers.
Another little-known fact about Saint Patrick; his official color, according to the Catholic Church, was blue - not green.
St. Patrick's life as a teenager evolved into a positive, fruitful life which you can celebrate annually on St. Patrick's day.