Before I understood the deep (and Christian) level of the Harry Potter novels, in other words before reading the Deathly Hallows, I found his relentless focus on his dead parents either unconvincing or pathological.
After all, his parents were killed while he was a baby, and Harry had no memory of them (until the memories were re-awakened by various magical means - such as the Dementors - later in the series).
The surface (sentimental?) explanation for Harry's growing fixation on his dead parents (exemplified by the Mirror of Erised episode in Volume 1) is that his adopted parents (the Dursley's) are horrible people who are deliberately mean to him.
But this explanation 'merely' implies the self-interested idea that Harry thinks he would have been more kindly and generously treated by his natural parents. This is almost certainly true, but not enough to bear the moral weight of a seven volume series.
If Harry's strong feelings about his dead parents really was based on the comparative nastiness of the Dursley's, then it would be, at bottom, 'merely' a desire for comfort and pleasure on Harry's part; which, while understandable (don't we all share it?) is not exactly admirable.
A deeper, but as it turns-out incorrect, explanation is that Harry has a kind of pathological, fantasy fixation on his dead parents - presumably as a consequence of having been-lied-to about them, or as a projection onto them of unrealistic levels of perfection.
There series of novels would then be seen as a progress away from over-idealised imagination towards a real understanding of his parents.
This would make the Harry Potter saga into a psychodrama of personal growth. But Harry is the hero, and it does not make sense for him to be motivated by something that is so purely personal. A hero saves his community - not only himself, and Harry's feelings for his dead parents are bound up with this.
The deeper picture which emerges over the course of the whole saga is that there are strong elements of destiny and heredity at work.
Harry begins by identifying with his father - for his exploits in Quiddich, his magical skill and as a dominant 'gang leader'; but ends by recognising that his father was also a spiteful bully and that the best in Harry comes from his mother: specifically his mother's exceptionally loving nature which has both affected Harry and been inherited by him.
This is symbolised by the fact that Harry looks almost identical to his father, except that he has his mother's eyes (and therefore, it implied, soul).
The people who best understand Harry (e.g. Dumbledore, Lupin and Snape just as he dies) recognise that Harry is 'his mother's son', but the people who misunderstand Harry (e.g. Snape until he dies, and Sirius) see Harry almost as a reincarnation of his father.
The stunning revelations of Deathly Hallows (prefigured in the graveyard at the end of Goblet) include that Harry's dead parents are not dead, gone and extinguished, but continue to live another existence 'beyond the veil' - aware of Harry, with some possibility of communication, and even able to provide some kind of support to him.
The deep metaphysical, and Christian, message of the Harry Potter series is that love has permanent effects: love affects everything and everybody forever.
Love may be overcome by evil, but is never destroyed by it.