For Voldemort, I always considered it like he has a goal (immortality), and a flaw (big ego). If he just wanted to be immortal, he'd make a few horcuxes and be done with it. He could be a recluse and study magic for centuries. But he can't just put pieces of his soul in any container. They've gotta be special, and important, and nothing is as special to old Tom as wizarding history. So he's got the founders' items, and the Gaunt ring, and they need special hiding spots, and so on. Further contrasting his goal, he can't just recluse himself from society, then he can't take over. His own ego and, well, evil-ness, means he makes enemies. This is one of my favorite writing techniques actually, where a character's goal is hampered by their flaws.
I personally think Voldemort is more complicated than this. I mean, I talked in the past about how I don't think he really wanted to live forever, and while, he would have loved to study magic, Tom can't be a recluse (hence why he returned from his world tour eventually).
I think Tom Riddle is someone who is desperate for human connection. I think, one of the things that hampers him the most is actually his need for recognition. his desire that others would know how great he is. He absolutely has an ego and thinks he's the best thing since sliced bread, but he wants everyone to know it too.
But his pride is a weird one. Like, Tom thinks he is the best, but he still considers himself not enough. He has a unique mix of self-hatred, a lot of pride and ego, and a huge dose of general spite that makes his mind fascinating, but also a hazard to everyone around him.
And I think, choosing Founders Artefacts wasn't for pride reasons or for Wizarding History (I think he cares about Magical Theory way more than any other area of magic, but I digress), but for sentimentality reasons (Dumbledore is correct about this assessment). Like Harry, Hogwarts was Tom's first and only home:
βI believe he had several reasons, though he confided none of them to Professor Dippet,β said Dumbledore. βFirstly, and very importantly, Voldemort was, I believe, more attached to this school than he has ever been to a person.Β HogwartsΒ was where he had been happiest; the first and only place he had felt atΒ home.β
Harry felt slightly uncomfortable at these words, for this was exactly how he felt aboutΒ HogwartsΒ too.
I mean, if we look at all the items he chose as Horcruxes the only common denominator is that they were all sentimental to him:
The Diary - something very personal to him that has no historical relevance. Hell, it's a muggle diary that I headcanon he found after WWII reached Britain and that the diary, like him, was a survivor.
The Gaunt Ring - Tom didn't know this was the resurrection stone, all he knew it as was a family ring of a line that lost all it's relevance. It was made into a Horcrux because it's a reminder of his family.
The Cup - a reminder of Hogwarts, his first home.
The Locket - both a reminder of Hogwarts and his family. I think the locket was his favorite Horcrux, hence why he went to all this effort to make proper protections for it while he didn't for the others. I think he cared about what this one represented the most.
The Diadem - again a memory of Hogwarts, but also his own pride. How he found a magical artifact thought to be lost. And he placed it in a similarly prideful location β a room at Hogwarts he thought only he knew about.
Nagini - a snake he felt affection towards, this one was made as a prize for her because he liked her, no other reason.
Most of the Horcruxes didn't have unique hiding spots. I mean, the Gaunt Shack, really? Lucius Malfoy's study (the diary) hardly even counts as a hiding spot. Both the Locket's cave and the Room of Requirement are places that are sentimental for Tom personally. Places that remind him of his own accomplishments. they aren't special for any grand historical reason, they are special for Tom as a person.
So, all in all, I think Tom is much more sentimental than he is prideful. I mean, he is both, but his pride is hampered by perfectionism and self-hate much more than most read him as. Like, part of his ego is that he is unwilling to think less of himself because he hates himself and he hates that he hates himself. Like, I don't think my reading of Tom Riddle is a super popular one, but it's the only one I think makes sense.
So much of his behavior just makes much more sense if you think he is desperate for human connection and recognition from others, especially when younger (with a pretty wrapped view of other people and how friendships work). And is a surprisingly sentimental guy.
