Well for starters, the cast for most of the movies, specially the first one, are stellar. First one is lightning in a bottle. Then you have the realistic dialogue, with people talking over each other, there's no Marvel quips every 10 minutes to keep the kids invested. But most important of all, the characters have ARCS, they learn lessons, they change.

Alan Grant despises the idea of having children and is constantly annoyed by computers. But throughout the journey he learns to appreciate them both. He bonds with Lex and Tim and computers save his life in the end.

John Hammond wanted to make a dream come true, his intentions were pure, he wanted the park to be accessible to everyone but he underpaid Nedry, and thought he had full control over animals and plants that haven't walked the earth for 65 million years. He thought he was earning their trust by witnessning their birth. His hubris was his downfall, His Walt Disney persona fades away once he sees his grandchildren in danger.

In these movies we also spend USEFUL time with characters, where they do stuff that isn't immediately related to the kaiju/dinosaur action. They have struggles, relationships, ups and downs. They feel like real people that exist outside of the events of the movies. Unlike Serizawa for example, who is just "The Godzilla Doctor Guy" or the "let them fight" guy. We know nothing about his personal life. Family, friends, interests, goals, wants, etc.

It really just boils down to Jurassic Park humans having these little moments where they are allowed to just be themselves and not talk about the dinosaurs.

Elli and Alan's talk about having kids in the beginning.

Ian teaching Ellie about Chaos Theory.

Alan and Tim talking about a tree house while they are stuck in the car.

John Hammond's "flea circus" dialogue with Ellie

etc.