As sort of companion piece to the previous Facts Are Not Enough there is this article from the Guardian that talks about how some widely held beliefs really have no basis in fact. I am sure you will recognize some of this wisdom from your own lives; here are some of the ones I have heard countless times:
Everyone must drink at least eight glasses of water a day (water is in food and other beverages)
We only use 10% of our brains (science still hasn’t discovered the ‘un-utilized’ 90%)
Reading in dim light ruins your eyesight (makes reading difficult, but not damaging)
Shaving causes hair to grow back faster and coarser (I’ve heard this mostly from women)
Eating turkey makes you especially drowsy (but Swiss cheese has more Tryptophan in it)
The article doesn’t cover one of my personal favorites, the all-too-frequently repeated and quite-well-documented-as-false claim that ‘Al Gore invented the Internet‘. Whenever I hear some repeat this, it just flips the bozo bit for them in my mind. Anyone who would parrot a lie that big is just a sad individual lacking in critical cognitive skills.
All of this goes to show that if you just blatantly make up ‘facts’ and repeat them enough, people will believe them (and repeat them).