Data-deduplication Memes

Someone just casually suggested storing ALL passwords in a single denormalized table with foreign keys pointing to it. The DBA just felt a disturbance in the force. Not only is this a normalization nightmare that violates every database design principle, but the "optimization" claim is wild—going from 100GB to 3GB by... deduplicating passwords? That means your users are sharing the same passwords at a catastrophic scale. Either you've got the world's laziest users all typing "password123" or you're about to discover why salting and hashing exist. Your security team would like a word. Your DBA would like several words, none of them professional.