In any population of dogs there are going to be some, who for whatever reason; a genetic predisposition, prior experience, health and vitality, will be tolerant of and successful with whatever we or the environment throw at them.
Some animals seem to thrive despite what happens to them, life gives them lemons and they make lemonade. My border collie Finn, is an example of this. We are his 7th home, if you include the rescue groups he lived with in between living with a person or family. It’s likely that Finn was never abused, but he certainly didn’t have the stability that some dogs might have fallen apart without.
We know that not all dogs are like this, and the challenge is determining which dog is going to take things in stride and which is going to be overwhelmed. It’s not always easy, and if you believe that because other dogs tossed into the deep end came up grinning and asking for more, that all dogs will, you run the risk of either drowning one or ending up with a dog who will never want to go to the pool with you again.