When I was growing up, my parents told me to allow dogs to "sniff" my hand before I attempted to pet them. Although it sounds like prudent advice (I guess they not only get your scent, but are warned before you surprisingly tough them), you can imagine my alarm at their advice becuase... I used to think "sniff" meant "bite". Not sure why, but I now never assume a child knows exactly what I am saying to them... :)
A childhood belief about cats and dogs

others believed things like this
- I used to think dogs had hooves, because they make hoofbeat-like sounds when they walk.— Samuel Lamont
- When I was a child my father warned me that if i picked my nose, my eye would fall out!— ras
- I used to think that growing pains meant that a tomato plant was growing in your stomach.— Annette
- I'm black, so as a child I used to assume that white people pooped peach the way I pooped brown.— Rick
- If you bite your nails, a hand will grow in your stomach.— Miss Laura
- I use to beleive that because oui (which sounds exactly like wee) mean yes in french, that poo meant no.— Toby