Some genius back in 2018 decided that inserting new rows into a table was far too conventional and probably slow for their precious microservice. Naturally, their brilliant alternative was to execute an ALTER TABLE statement every time a user made a purchase, appending a new column named after the transaction ID and timestamp. You can probably picture the sheer joy of trying to write an analytical query against a table that had accumulated over forty thousand columns before PostgreSQL mercifully threw an error and refused to create any more. The best part was finding out they handled refunds by dropping the column entirely, which of course locked the entire database for twenty minutes during peak hours. I spent three days writing a migration script to un-rotate this absolute masterpiece into a normal structure while the original developer calmly explained to me that schema flexibility is the future of data engineering. My hammer almost got a workoout that afternoon.