some one already mention stepping on cracks in the pavement... my friend was told if you step on the cracks you'll marry the devil
My brother told me that my teeth had gone black because I had brushed them twice (y'know to be extra good

) I believed him and so went back and brushed them again (I was too short to see in the mirror) then he said they were even worse

I must have spent an hour that night brushing my teeth
Same brother told me that the zipper on my cardigan was a caterpiller dipped in metal and that they get angry (presuimably from being dipped in metal) and 'get you' I remember standing in the garden screaming and screaming because I was petrified of the zip, but couldn't take the cardigan off (because, I'd have to touch the zip)
I was told that everything on my plate was chicken, so that I'd eat it (brussell sprouts DO NOT taste of chicken - I threw up)
School-day's are the best days of your life. Told to me by loads of people but granted not my mother - In fact one of the few nice conversations that I had with her when I was young was that school-days are the worst days of your life and it does get better (quite a good thing to hear from your mum when your a messed-up teenager)
Golly, that turned into a bit of a therepy session (sorry!

)