When my now-teenage kid has argued with someone, I always let her vent to me. She knows I am her biggest defender. Once she calms down, I try to present the other side of the story, if I see there might be one. She doesn’t always appreciate this. When someone you believe should be on your side presents a viewpoint that differs from yours, it can feel like an attack.

Sixteen years ago, I received a phone call to say that a pregnant Border Collie had been dumped at a local pound. She was safe with a foster family and was due to give birth any minute. This meant that in a couple of months, there would be puppies that needed to find new homes.

About ten years ago, I went for a very routine doctor’s appointment. I’m generally pretty healthy, and there wasn’t anything particularly...