I just remembered one that terrified me. Loud thumping, especially (but not exclusively) rhythmic thumping. For example, we had "enter phones" in our apartment building. It operated on a buzzer type system and there was a unit on the back wall of the laundry room in each building that operated it. When a visitor came for one of the 11-15 apartments per building, and they pressed one of the apartment numbers, it would go "thump-thump thump-thump". I remember running screaming from the laundry room on many occasions, terrified and shaking. My dad would be so pissed at me, but my mom tried to understand. They'd say, "But honey you know what it is, and it isn't scary, why do you act like this?" I just said it's scary! Similarly we had large fans in the lobby which vented heat from the lobby and attic in the summer. They opened based on heat at any given time. I never knew when this was. I was terrified of it though - the noise and the appearance of it. Heck, even now thinking of these things makes me tense up!
Thank you for this thread. I had forgotten these things and now when my daughter freaks out over sounds that seem so benign, I'll be a little more understanding.
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They tell me I think too much. I tell them they don't think enough.