That cracking your knuckles gives you arthritis.

A lot of cryptocurrency scams. Majority of the suckers often either continue to hold their investments; that was worth less than dirt, or go on to invest in yet another scam.

Personal carbon footprint or any green initiative which focuses on individual action. BP invented the entire concept during a marketing push to hide the fact that like ~72 companies produce 90% of pollution.

The earth being flat. We have literally done studies, taken pictures, boiled all of that down to the level that a kindergartener can understand it, and some idiots still don't get it.

Detox. What do you think your liver and kidneys are doing all day? If they weren’t working you would be on a form of detox called dialysis. edit: To clarify since it might not be obvious, I’m referring to pseudoscience detox teas and pills. Not medically justified detoxification like opioids, alcohol, acetaminophen, etc…

Crystals. They are just f*****g rocks. There is no scientific evidence proving that they have healing effect. Any possible effects are due to the placebo effect. People will actually go against medical advice because they think holding a crystal will fix all their problems.

"Catching a cold" from cold weather. It's a pathogen. You catch it from people. Though disease does increase in the winter. It's commonly thought to be due to close quarters indoors and less Vitamin D from the sun, important for the immune system.

Homeopathy. It's water.

We only use 10% or our brain.

Isn’t that whole Myers-Briggs personality test recognized as a complete fabrication.

That vaccines cause autism.

Different parts of your tongue don't actually detect different types of taste. Your tongue is the same all over.

Lie detectors.

Shaving making hair grow in thicker.

Wolf hierarchy with alpha on top and omega at the bottom.

That cows just produce milk naturally without being impregnated and giving birth first. they are simply mammals, and produce milk for the sole purpose of feeding their young.

That dogs can only see in black and white. This is false.

Touching a baby bird will make its parents reject it.

That you swallow 8 spiders a year in your sleep.

The food pyramid.

That people are “right” or “left” brain thinkers and that it has any bearing on her personality and level of logic or creativity.

That MSG is bad for you. I meet people regularly that think it's a super insta-cancer ingredient that will cause you to die or something based on 80s/90s false scares. Then I tell them "you do know it naturally occurs on tomatoes, yes?"

That carrots improve your eyesight. I think it was used in the Great British blackout because there was a food shortage and carrots was the easiest thing to get. Don't quote me on that tho.

It’s illegal to keep the light on in the car while driving.

If you pull out a grey hair three more grow in its place, my sister still believes this one.

Professional fighters don't actually have to register their hands as weapons. No body part can be registered as a weapon. I'm upset with myself for actually believing it for years.