Single table Memes

Just like that Polish town where 6,000 people share a single street address, single-table databases cram everything into one horrific data structure. No relationships, no normalization—just a massive Excel spreadsheet masquerading as a database. The database equivalent of putting your entire life in one drawer and then wondering why you can't find your tax documents. Bonus points if you've added a JSON column to store "flexible" data, you monster.