That's more of a "believing lies told my adults around you" case.

Carrots will allow me to see in the dark if I eat enough of them.

This was (and is) a very successful British WWII misinformation campaign. The Brits didn't want it known that their aircraft had radar - which allowed them to find enemy aircraft at night. So they embellished carrots' benefit on night vision to cover up their technological advantage.

It worked. Don't feel bad for believing it. Everyone believed it.

If you were cold then you would catch a cold.

There is a startling amount of people here (most people I know) that believe this. I work in healthcare and we constantly have arguments about the AC in summer for that exact reason. Yeah cold weather can make it easier to catch a cold but it's interesting to see how many people believe that you need to get warm to avoid catching a cold.

Carrots will allow me to see in the dark if I eat enough of them.

Partially true. If you're vitamin A deficient, your night vision worsens and carrots can help with that. But you won't get Minecraft night vision

Believing in karma isn't bad, though. If it helps being a better person, then why not.

99% of Indians still believe the first one. They also believe that if you don't immediately dry your hair right after a shower you'll catch a cold. Sneezing and coughing without covering your mouth though? That's ok.

The world believed carrots made you have better vision. It is an interesting story and worth looking into.