Last summer, the family and I found ourselves in Durango, Colo., in the southwest corner of the state. Thinking to take in a bit of the local pageantry, we headed to the Bar D Chuckwagon for dinner. It was exactly what you’d expect — outdoor seating, cowpokes ladling out hearty food on metal plates: chicken and steak, beans and biscuits. Our tablemates were mostly retirees, and while our politics were, shall we say, not in harmony, we managed to carry on general conversation without taking our butter knives to each other’s throats. Respect the elderly, I told myself, repeatedly, through...