“This is the hardest part,” I said softly at the end of my explanation. Eyes glistening, the husband nodded. His wife couldn’t look at me, and I could hear their kids out in the lobby...

Just last week, while I was performing euthanasia for a critically ill patient, the pet’s owner looked at me and said, “I bet this is the hardest part of your job.” That gave me pause. For me, putting...