I can't remember anything in particular that frightened me as a kid. I don't think I was particularly fearless; I just don't remember anything in particular. I enjoyed crawling through small spaces and loved heights, I got left behind with regularity (fourth of four) and always found my way home (no abandonment issues), etc.
However, the hamburger thing does remind me of a revelation I had as a child the first time I realized you were supposed to put the mustard on the the baloney, and not on the bread. I thought the mustard was there to make the bread taste better. When I realized it was there to make the meat taste better, I was simply amazed. What a concept! It's weird what impresses a kid, and what the adult remembers.
Clowny's Kool-Aid Man story reminded me that as a kid, I mixed all the flavors of Kool-Aid together, just to see what would happen. The result was a murky brown liquid that tasted nauseating. When I poured it out in the back yard, it killed the grass.
For many years, I couldn't look at, let alone eat, scrambled eggs. Fry 'em, boil 'em, heck serve 'em to me raw and that was just fine; but scrambled would make me gag.
I'm pretty sure I know why, though. Sunday morning breakfast was a big to do at my grandparents house. The whole family would attend church together, gathering at my grandparents home for her weekly breakfast feast, thereafter. Bacon and eggs with ham, pancakes, oatmeal, etc. If you would typically eat it for breakfast, my grandmother would prepare it. The problem was, she couldn't cook. Most of my family preferred their eggs scrambled, so that's what they got. Always so runny that you needed a sponge to eat them. To top it off, both my uncle and grandfather liked ketchup on their eggs. Their plates reminded me of lumps of bloody chicken flesh swimming in embryotic fluid. Needless to say, I opted for the oatmeal.
It used to upset me when I would get the same prize in my cereal box week after week, in spite of the box offering one of several different prizes.