I once had two FB friends get in a debate on my wall. My post was, "Well, Daughter has another ear infection." The two FB friends were parents of friends of mine.
Friend's Mom: You should get them to stop drinking milk and cut out all dairy. That's why your kids are so sick.
Friend's Dad: That's crazy talk. Mainstay, feed your kids what you want.
Friend's Mom: Documentation website I cut out dairy and can now jump over buildings
Friend's Dad: Well I eat 17 pounds of cheese a day and have the body of a 20-year-old superhero
and on, and on. It went on while I was at work, so by the time I got to it, they had argued through much of the day. I deleted the whole thing. I just think it's funny that it was the milk thing, but I didn't even start it!