That Einstein was rubbish at maths. He wasn't. In fact he excelled at maths, along with other subjects.
That creationism is a viable alternative to evolution (in the US anyway, and even though I don't live there, that amount of stupidity just makes me sad).
That good and evil are real, and not something we've made up, that they're inherently there, whether we are or not. They're both meaningless terms and their definitions vary from person to person, from generation to generation and from culture to culture. NOTHING is inherently good and NOTHING is inherently bad.
That YOUR KID is the most speshul kid in the world, the smartest, coolest, most unique, et cetera. He or she IS NOT, it's just yet another stupid little kid, nothing more, nothing less, the only thing to differentiate it from others of it's kind is it's genetic relation to you which makes you THINK he or she is totally awesome, et cetera. So shut up about your kid already, he or she is nothing special.
Which brings me to this one - the misconception that humans AREN'T idiotic in general. That everyone is somehow unique. Noones truly unique(save for DNA, obviously), not you, not me, not anyone. Every thought you've ever had, someone has had before you. Every. Single. One.
There are more obviously, but since it's 6:47 am and I just got through watching a film called Braindead(which is absolutely AWESOME, and completely INSANE), I can't think of anything else at this precise moment.
