Sweet, sweet, sugar
I once found a small dish of powdered sugar in the refrigerator, and decided Mum wouldn't miss a spoonful of it. It turned out that it was baking soda she was using to deodorize the fridge. There wasn't enough stuff in the world to take that nasty taste out of my mouth.
D

Creaming Soda
When my parents were having a party I took a big swig out of a glass that resembled the one I was drinking from, filled with creaming soda. Only it wasn't creaming soda, it was something beer, which tastes horrendous to a 5-year old. Although I did get a good buzz!
B

Our enemy, the pig
I love ham. When I was younger, I saw my Mum cutting small pieces of ham from a larger slice. When she wasn't watching I swiped some of the off-cuts, shoved them in my mouth and started chewing. That's was until I got to a bit that was about the consistency of snot-covered plastic. She was cutting up bacon and the off-cuts were the gristle. I still like ham.
D

Ohhh, surprises
I grew up in a household that was poor enough so that kids did not often get soft drinks (not a bad idea, of course, but this wasn't due to health concerns, but money). Of course sugar-laden soft drink is what children crave more than anything else in the world, so the tradition was that when an adult put down their Pepsi/Coke or whatever and left it and you came upon it you grabbed it and took a swig as fast as you could. Oh, did I forget to mention that my parents were also chain-smokers? Ack!
D

More Oooh, surprises
I had swiped my brothers glass of chocolate milk that he had left behind a little while ago. I had just reached the bottom of the glass of chocolate milk... you know, when you get to the lumps of chocolate powder that haven't quite dissolved? I loved those little choco-lumps like life itself!
One of them CRUNCHED! "WTF", I thought.
I digitally inspected the contents of my mouth; and pulled out a HOUSEFLY!
D

Cherries?
When I was about 4, we were visiting my grandparent who had a big vegetable garden. They had just finished harvesting some of the vegetables, and had several baskets of produce on the porch. One basket contained some wonderfully yummy looking bright red cherry like things, which I headed straight for.
To her credit, my mother tried to stop me, but I was too fast and too determined, and popped a whole hot cherry pepper into my mouth. Oh. My. God. To this day I refuse to eat anything with Chili in it.
D