Is it normal that alarms terrify me?

I noticed this one thanksgiving when a plow truck (it was snowing) with flashing yellow lights scared the hell out of me. Why? I don't know. Then, at home, a year later, the septic tank alarm (Tank alert I, look it up) let out a PIERCING screech mixed with a LOUD buzz... I was shaking like a leaf, and couldn't bring myself to flip the silencer switch. For two weeks after I was afraid it would go off again, NOT that septic backup would come into my basement shower. Is it normal?