You want a citation? Ok, common knowledge and generally accepted facts need no citation. This is especially true when the information is something readers should already know, readily accept, and easily find in general references (like the Internet or paying attention in life).
~APA Publication Manual (5th edition). I might have embellished the last part.
One example of common knowledge and a readily accepted fact would be that modern cars are far more reliable than cars from the 1980s. So if you want to bring anecdotal evidence that flies squarely in the face of common knowledge, then the burden of citation is upon you.
I hate to be a douche about it, but you kind of asked for it. And technically speaking, I asked you to "site" it. Not sure what the hell I was thinking there.