Post-it notes were invented by accident.

That's true! A scientist named Spencer Silver was trying to make super-strong glue, but he accidentally made a very weak glue that didn't stick well. Years later, a colleague had the idea to use this 'failed' glue to stick small pieces of paper that could be moved around again and again. That's how the Post-it note was born, an invention that started as a mistake but is now found in many offices and homes all over the world!