James shaming a farmer into helping a neighbour hit by foot-and-mouth disease, and later losing his temper with the same man for threatening to sue him. In both cases he got a sincere apology — and he never raised his voice, never lost control, never broke character.
In an early case, James is able to deduce that an ailing bull who has a dangerously high temperature is suffering from sunstroke and saves him by simply running a waterhose on him until he cools down. Later the farmer who owns the bull objects in a lecture about using modern methods by citing James who apparently just needs simple things like epson salts and cold water for his treatments.
Tristan taking on a farmer who was determined to sue the practise. In one conversation he effortlessly makes the man back down completely and then tops it off by billing him for the visit that the farmer had been suing them over.
A farmer is simply refusing to believe Siegfried that his bull has swallowed a piece of wire and needs an operation. Later Tristan comes back with a metal detector and proves Siegfried right, in front of all the farmer's friends.