How about these "myths" - if anyone has evidence that these aren't myths - would love to see it.

You lose most of your body heat through your head

You should drink at least eight glasses of water a day

If you go out in the cold with wet hair you will get a cold

Carrots can improve your eyesight

Eating spinach can make you stronger

You should finish the course of an antibiotic - other than for things like endocarditis and prostatitis you can stop antibiotics once asymptomatic for 48-72 hours

Sugar makes kids hyperactive