10 Common “Facts” You’ve Believed Your Whole Life—But Are Totally Wrong

We all grow up hearing certain “facts” that get repeated so often, we just accept them as true. Some come from school, others from media, and many are just passed around by friends and family. But the truth is, a lot of what we think we know is... totally wrong. Here are 10 widespread myths that have been debunked — and might leave you questioning what else you've believed without proof.

1. Humans Only Use 10% of Their Brains

This idea has been spread in movies, books, and even motivational speeches. But it's not true. Brain imaging clearly shows that we use all parts of our brain, just not all at once. Even when you're resting or sleeping, different regions stay active. The "10%" myth is catchy, but it's pure fiction.

2. Goldfish Have a Three-Second Memory

Poor goldfish! They’ve been insulted for decades. In reality, goldfish have pretty decent memories — they can remember things for weeks, recognize routines, and even be trained. This myth likely started to make people feel less guilty about keeping fish in small bowls.

3. Bulls Hate the Color Red

You've seen it in bullfighting scenes: the matador waves a red cloth, and the bull charges. But bulls are actually colorblind to red. They react to the motion of the cloth, not the color. It's movement that annoys them — not a specific hue.

4. Shaving Makes Hair Grow Back Thicker

This is one of the most widely believed grooming myths. When you shave, you’re cutting hair at the surface, not changing its root or growth rate. The blunt tip of shaved hair might make it feel rougher or look darker, but it’s not actually thicker.

5. You Swallow Eight Spiders a Year in Your Sleep

This creepy myth has been shared online for years, but it's totally made up. Spiders generally avoid humans and have no reason to crawl into your mouth. Plus, the vibrations of breathing, snoring, and movement keep them away. You’re safe — really.

6. Lightning Never Strikes the Same Place Twice

Lightning doesn’t keep a checklist. In fact, it often hits the same spot multiple times — especially tall buildings or metal structures. The Empire State Building, for example, gets struck around 20–25 times a year

7. Cracking Your Knuckles Causes Arthritis

That satisfying pop might annoy people around you, but it won’t give you arthritis. The sound comes from bubbles in the joint fluid, not bones grinding. Studies show no link between knuckle cracking and joint disease.

8. You Need to Drink 8 Glasses of Water a Day

Hydration is important, but the “8 glasses” rule is a generalization. The right amount varies depending on your diet, activity level, and climate. Many foods like fruits, soups, and even tea contribute to your daily hydration — so you don’t need to obsess over that number.

9. Hair and Nails Keep Growing After Death

Creepy... but wrong. What actually happens is the skin dries and pulls back, making hair and nails appear longer. But there’s no growth — cells stop functioning shortly after death.

10. If You Touch a Baby Bird, Its Mother Will Abandon It

Mothers don’t abandon their babies just because a human touched them. Most birds have a limited sense of smell, and their parental instincts are strong. If you ever need to help a baby bird, it’s usually okay to gently return it to its nest.

Final Thoughts

It’s wild how many “facts” we take for granted, just because we’ve heard them so often. Questioning common knowledge isn’t just fun — it’s necessary in a world full of misinformation. So next time someone drops a random fact at a party, maybe take a second to check if it’s actually true… or just another myth waiting to be busted.