When I was quite young, I was in Texas, or maybe Arizona, somewhere hot and dry anyway, and I was at a gas station, and someone gave me a bottle (can?) of Dr Pepper to try for the first time. I sat down to drink it, not knowing that I was sitting on a fire ant nest.
Needless to say I got bitten! And forever more the taste, even the concept, of Dr Pepper was associated with those ants — and I’ve never drunk it since. That’s the memory that came back reading this story, so I totally get how certain tastes bring back those key moments.