My dad's only problem was that he knew that his dog was going to most likely bite him, etc because he wouldn't understand my dad was helping him. My dad knew he was going to be taking several bites for the team in order to get the chicken bone out. Growing up on a farm teaches you that animals, no matter how wonderful they are, are animals with an animal instinct. Fight or flight instinct kicks in when they are distressed. I speak from experience with that.
My dogs know that *I* am boss. At most, they would "nip" or "mouth" me when in serious pain. Weird as it sounds, they don't even "yip" if you step on any of their feet by accident. Any more than an "I'm in pain" mouth action, they will be put down. I honestly think they know that, too.
Fortunately, that scenario has never occurred, though I've been forced to put down many critters. Never for any violence or danger towards humans or other critters, either.
Then again, I've only dealt with about 2 dozen dogs as pets. My brother, my girlfriend, and I only have 5 right now ranging in size from 8 lbs to 130 lbs, so we're not NEARLY as experienced as you.