I used to have to manually focus to take photos of my dog. The apparent noise from the early Ring USM AF in the 85mm/1.8 lens drove him mad and he would run out of the room.
We did initially wonder if it was some psychological effect of pointing a camera at him, but one night I hid behind a curtain and used the AF motor and he still shot out of the room.
Subsequent USM AF motors were silent to him and he was then content to have his photo taken.
My dog also developed an aversion to cameras, and I wondered if it was the USM focusing. That might have been what started it, but she still doesn't like any cameras at all, USM or not.
We did initially wonder if it was some psychological effect of pointing a camera at him, but one night I hid behind a curtain and used the AF motor and he still shot out of the room.
Subsequent USM AF motors were silent to him and he was then content to have his photo taken.