I think it was often the look on my face. I can’t really remember ever “talking back” to an adult, but it’s hard to imagine any kid not wanting to at some point. I suspect there must have been something on my face that indicated I wanted to “talk back” that caused my grandmother or my dad to shake a finger and issue that warning.
It turns out that there are some times though when talking back might actually be a good thing.
Many counselors are trained in a technique called mirroring, when they repeat back (sometimes paraphrasing, sometimes word for word) what their client has just said to them. While some people may experience that as annoying (is there an echo in here?), it can also be a way to demonstrate that a person has been listening.