[kanawa]

Daisy had been a very lovable, and well loved, dog, until she suddenly snapped.

By your own admission she was not a naturally mean dog
but rather a naturally loving dog until something triggered an attack.

[Dr. Bogus Pachysandra]

“a naturally loving dog until something triggered an attack.”

Yup! Doug’s talking on the phone “triggered an attack.” If only he hadn’t been on the phone, she never would have “snapped!” Right.