While of course not every American fits the stereotypes set by non-Americans, there are some cultural differences that occasionally confuse people from the United States despite seeming perfectly normal to everyone else. Not using the metric system, going into debt over a broken bone, tipping 20% of the check for service at a restaurant, adding sugar to every food, wearing shoes inside the house, drinking iced coffee all winter instead of hot tea, always opting for toilet paper over a bidet--some classically "American" habits are just plain weird.
So, when a Reddit user asked, "What's something normal the rest of the world does, that Americans are confused by?" non-Americans were ready to share things that perplex people from the United States.
Boiling water in an electric kettle. - Stu_Thom4s
Taking off your shoes in your home
My friend's carpet is a murky shade of green and hard as rock - IllegitimateAd