i remember learning some things, making some discoveries that were wonderful, in that they were knowlege and i am always happy to recieve new knowlege.. but horrible, that the things were really real, that they actually existed. here are a few examples:
vampire bats (because i thought they were nightmare things, but they turned out to be real)
bedbugs (because they have that cheery sounding bedtime saying, and it's not at all as cheery in real life)
there are more, but these are my examples that i was able to give in this 3 minutes of my time. tell me about yours! what is great to know, because you know, but bad, and evil because of it, too? another fine example!:
ring around the rosie. for obvious reasons.