MSG. People will swear it gives them all manner of ailments

Socialism.

LGBTQ people and drag queens.

In South Korea most fans have timers so they're not left on overnight, because people think it'll kill you if you do leave it on.
This belief wasn't helped by medical examiners putting "death by fan" on the death certificates of suicide victims to help the dead save face and spare the families the embarrassment of a "cowardly death" for a few decades.

For my country (Germany): Catching a draft. Basically people believe that a light breeze from an open window will make you ill.

Living near a nuclear plant.

Little do they know, that they get more than 50x more radiation effect from the natural surroundings and the rocks in earth than from the nuclear plant 🤭 And our body is really capable of dealing with that since the beginning of our evolution (DNA repairs and co).

https://pages.vassar.edu/ltt/files/2011/04/Screen-shot-2011-04-21-at-1.18.09-AM1.png

here is a chart showing radiation intensities for various sources of radiation

as a chemist by trade: all sorts of random chemicals

also some people believe that microwaves are harmful and 5g towers will turn all your frogs gay or something like that. gee i wish they were consistent in their beliefs, if they were i'd never find them on internet

Staying in hostels when traveling overseas. The amount of people who tell me I'm crazy and going to get murdered if I stay in a hostel is ridiculous.

Hostels are great, and not any more dangerous than hotels are, you just have to look at reviews and go for the type you want. You can also rent private rooms at a lot of them. I always stay at one's with a kitchen so I can save a bunch on food, too.

5G, Vaccines, MSG, WiFi, Socialized Medicine, Jews.

The Tor Browser, it's just a normal Browser with some functionality to improve privacy.

Swimming around in a spent nuclear fuel pool: https://what-if.xkcd.com/29/

Jet fuel.

People seem to have the impression that it's some extremely explosive stuff that has to be handled with the upmost care, but it's just highly refined kerosene. It can be used as a replacement for Diesel fuel in many cases - in fact, U.S. military vehicles can run off either. We put it Toyota Hylux pickups up in northern Greenland because it doesn't gel up like Diesel fuel.

Australia. Maybe not completely harmless, but far less dangerous than non-Australians make it out to be.

Video games. There’s absolutely no evidence that they make people more violent.

Nuclear power in general.

Sharks.

More people die due to things like selfies, falling out of your bed, tipped vending machines and heck, even balloons, then to a shark.

Just because something can kill you doesnt mean it will, more often than not, it actually wont.

Huntsman spiders

They are large, and they gallop across your ceiling like demented gazelles, chasing down cockroaches.

However, they're nonaggressive to humans, you'd have to seriously harrass one to provoke it into biting you, and the worst they could do to you is a beesting-like bite.

They're also all named Kevin.

The dark. Everything seems more scary in the dark

Scuba Diving. Lots of people have heard that your lungs can pop or something similar and it makes them really afraid to try it. If you hold your breath, you may have issues with your lungs but your SCUBA apparatus is such an amazing design that even if you need to throw up underwater it's designed to filter your vomit through the apparatus so you can continue breathing even after throwing up THROUGH it (which you should do if you feel nauseous down there). Just keep the apparatus in your mouth and don't stop breathing and you'll have a great time.

Scuba Diving is one of my favorite things to do and I really think more people should try it!

Spiders.

Even black widows basically have to be harassed into biting.

Dihydrogen monoxide except for when it completely replaces the air.

Canadian Geese. They are super aggressive but cannot hurt you.

Cellphones in a gas station. Also double dipping in a sauce or dip.

People who are dependent on opiates and opioids.

Some people who are in a lot of pain legitimately need the medicine in order to have a normal life. It doesn't make us high, it makes us 'normal' because we actually require the medicine to bring us to normal levels of activity.

Just because someone is physically dependent on the medicine, does not make them an addict too

Most of us would rather never take another pill in our lives if we were suddenly healed.

Wild strawberries. As far as I know there are no wild strawberries that are poisonous. There are two types, wild strawberries that resemble normal strawberries but smaller, which taste delicious, and mock strawberries, which taste like water but are also safe to eat. Mock strawberries can be recognized as growing upward and having protruding red seeds.

Muslims.

Most US cities are not as dangerous as the news makes them out to be.

Climbing, the gear is all rated to lift 2 tonnes, so a medium sized car. It won't snap with you on it.

Edit: sorry this is misleading, climbing is not harmless, and a lot can go wrong even with good equipment. The point I wanted to convey was that equipment failure is an unlikely cause of problems for climbing

According to my mother, gay marriage. Nuts on mustaches is just the end of the world to her for some reason.

Otherwise, she's a sweet lady.

ITT: people that don't know what completely harmless means