Something that always tugged on my heart with danse is that after he learns he's a synth and is processing it he's not just upset that some of his memories aren't real. He's upset that his memories are lonely.
He was upset he wasn't given any memories of family, siblings, or friends in his fake childhood. He was upset that he'd been given this false perception of being completely alone his whole life and then suffering emotionally because of it.
He was made to feel lonely for so long because his memories we're lonely.