Drinking milk.  War time and food was scarce but there was plenty of rich creamy milk from the dairy farm next door.  I was seen as a sickly kid, lots of vomiting and diarrhoea mostly at embarrassing times & places.  Milk was so good for you.  I would drink a glass to please my G'ma and then later hide up behind the chook house as my stomach grumbled, bloated, became nauseated then the relief after a good projectile spew.  My Dad, a kindly teacher, made arrangements with the local milk company for every school kid to have a drink of milk.  (This was way before govt school milk was introduced).  Milk , milk, everywhere!!
As a teenager, having a milkshake with the boys was fraught with danger. Once I ended up in the gutter but not for the reasons my mother feared.  I then stuck to the uncool lemonade.
Years later when I was all growed up, I was diagnosed with dairy allergy, as was one of my kids and one of my grandkids.  Ah the good old days. Gazania