Lies you were taught
Wikipedia maintains a list of common misconceptions, some of which you likely hold. Remarkably this is the case even if you have read the page before, as I’m now discovering upon review.
Some highlights: You do not need to wait 24 hours to file a missing person report. Medieval Europeans did not believe Earth was flat. Sugar does not cause hyperactivity in children. Swallowed chewing gum does not take years to digest. George Washington Carver did not invent peanut butter. MSG is harmless.
Read the entire thing and update your beliefs accordingly.