This analysis may be more rightly accredited to DC, who came up with the actual theories described therein. I have merely taken the steps to organize said theories into a complete analysis. This analysis concerns both the novel and film “versions” of the series (although the two are so exactly alike, it is stretching matters to label them as “versions”). Of course it goes without saying that the entire Harry Potter franchise belongs to J.K. Rowling and Warner Brothers, respectively.
Notice, if you will, the first scene in which Draco Malfoy meets Harry Potter, in Harry Potter and the Sorceror’s Stone. Draco is quick, even eager in his attempt to strike up a friendship, or at the very least alliance, with Harry. Draco notes that Harry is well-known and that his name is obviously influential. Draco then offers his assistance in guiding Harry through the regimen of the school (albeit in a mean-spirited way). However, his offer is refused in favor of a friendship with Ron.
Note that Draco as yet has no apparent reason to seek an enmity with Harry, even after his offer of an alliance is rejected. He seemingly decides to hate Harry of his own accord, for no reason aside from a rather shallow Gryffindor-vs.-Slytherin tradition. However, let us look at this from a different perspective.
Consider the way Draco reacts to those he considers his superior, whether in title, rank, cleverness, or age (Snape, his father etc). He is highly deferential, even obedient, and is the picture of docility, all too willing to please. Draco is more of a follower than a true leader. He wants to be lower in rank, and why not? Leaders are prime targets for the oppositition, and Draco, through a sense of nonambition and plain reason , prefers a lower position. While he will reluctantly shoulder the burden of leadership if he sees no other (in his eyes) qualified candidate, he will willingly foist the burden--and thus the responsibility--onto another qualified individual, if he believes they are worthy.
Harry Potter is obviously such an individual. He is world-famous, and has apparently deserved renown as a powerful, if still immature, wizard. He is the school’s golden boy, if you will, prophesied to rid the world of corruption--if you will pardon an expropriation of a certain phrase, “bring balance to the Force”. A person of his influence would seem to make a fine leader, and Draco offers the responsibility of leadership to him, preferring instead to follow where Harry leads.
Harry blatantly rejects Draco’s offer to govern his little gang, and befriends a rather, in Draco’s opinion, sorry lot of people, unworthy of someone of Harry’s importance. Draco is affronted both by Harry’s refusal and his alternate selection. This is an unforgiveable offense.
Draco probably also feels a certain sense of obligation to maintain a position as leader, because his father is so prominent in wizarding society and he must therefore follow in his father’s footsteps. He does not want the task, but less than the highest standards are met with disapproval.
Draco is a leader by default, thrust into the position because of his father’s status and the fact that no one else in his house is willing to take the job. He knows he’s not a very good leader, so he seeks the obviously deficient--mentally, socially, physically--to follow him. His henchmen are bullies and intellectually dull lugs, giving him a sense of superiority.
Draco also has a good deal of respect for the teachers in his school, even the ones he doesn’t like. In Prisoner of Azkaban, he twice ceases his verbal attacks on Harry when he sees there are authority-type witnesses--respectively, Professor Lupin and Hagrid (who has been promoted to a Care of Magical Creatures teacher at this point). He personally dislikes both teachers (whom he sees as favouring Harry), but he is not stupid enough not to recognize their authority. He maintains a veneer of deference to authority figures, which is sensible because after all he is only a student, and of course does not wish to be detained or expelled (which would no doubt result in further punishment at home, and likely severe at that).
Just saw the second Harry Potter film again with DC (making it twice with her and once with Mom). She brought her 15-year old brother along, and he’d only read the first book, so we had to explain a bit to him on the ride there. It was still quite fun. I spent a lot of time mewing at Lucius Malfoy’s scenes, and afterwards DC claimed that she wanted to a) learn Parseltongue and b) go to the house of Slytherin. Muchly fun. Unfortunately, a good bit was ruined from having to glare at what seemed to be the entire sixth grade of the Children’s Centre for the Profoundly Socially Retarded, seated directly in back of us. They talked their way through the ENTIRE FILM. It was like they had studied the script, but they were a bit slow on the uptake, so they repeated lines and made unnecessary comments (example: Harry opens a door. “Look! I wonder if he’s going into that room!” Harry enters the room. “I wonder what he’ll find in there!” Repeat ad infinitum) and discussed their interpretations of the film at length at the tops of their voices. What REALLY pissed me off was when one commented, during a Lucius Malfoy scene, “He looks like a girl!” At that point I turned and snarled. Think I scared a few of ‘em too. Heh.
Oh, and Tom Riddle? Holy flurking shnit! There must be something in the water at Hogwarts, because I don’t remember any of the guys from my high school looking remotely like that at sixteen, or eighteen, or, well, ever. Between him, Malfoy and Snape...can I be in Slytherin, too? :)