Harry Potter's motives are to seek revenge on his parents's killer, Voldemort. His fervor determination is the "cause of events that unfold around [him]" because in turn, Voldemort wants to kill Harry since he didn't the first time. And when Harry enters school, he meets Professor Severus Snape, who immediately dismisses Harry’s celebrity with an obvious dislike, and we begin to question his motives. Later we find Professor Snape at the scene of every mystery, such as having a scratch on his leg when a Troll was out or silently chanting while staring intently at Harry during his Quidditch match. With Snape at the center of all the conflicts, we take Hermione’s side, believing her belief that Snape is trying to kill Harry Potter. With motives we don’t understand until the end of the book, Professor Snape turns out to be actually protecting Harry from Professor Quirrell/Lord Voldemort.
Though Snape's opposition with Harry is in every book, the very last one reveals the ultimate reason behind his actions. The third person perspective keeps the mystery alive for the entire series with an enigma code, as we are “alongside [Harry] in trying to solve the crime or mystery” of the Horcruxes, Tom Marvolo Riddle's story, and Snape’s true allegiance. Finally, in the span of the seven books, the equilibrium of Harry’s happiness with his father and mother is disrupted by the years of disequilibrium fighting Voldemort and living with the Dursleys, but equilibrium restores when he defeats the Dark Lord and gets married happily ever after. (I hope that's not a surprise!)