How about you @Air, what is your personal line in the sand?
Working on that honestly, I don't really know. There are just so many factors, I'm not sure I can come up with one firm answer. Like I think yelling could be abuse if it happens really excessively, but a little bit is definitely not, so to actually know I'd have to measure the frequency, length of yelling, decibels, and know why it was happening. Similarly a time out isn't abusive obviously, but I think making a child do a time out for like 5 hours would be, so I don't know where the cut off point is there too, and it would also depend on the circumstances. There are some things though that I think are just inherently abusive without a gradient, like hitting your kid out of anger, or purposefully insulting them. Generally I think there are some things that are clearly abusive, and some things clearly aren't, and there's just this massive grey area in the center. It's not much help I know, but that's the problem, it's just so vague.
And yeah I am a survivor of child abuse btw.