I found this particular dog to be a challenge to train because of his superior intelligence. Training him was more like a chess game. You had to be 3-4 steps ahead of him or he'd make you look silly.
So, the chap called today to share something he found quite entertaining. While grouse hunting recently, his dog bumped a bird but the owner broke my cardinal rule and shot it!?! In his words, the dog subsequently went over to a near-by tree and sat down. ?!?
The owner sent his dog for the retrieve but the dog completely avoided this dead bird. This is a dog that typically retrieves to hand! So, perplexed, this chap picked up his own bird.
A short while afterwards, his dog nailed another grouse but did not bump this bird. The owner walked up, flushed and dropped this second bird. He sent his dog for a flawless retrieve to hand.
….there you go. You could say, "This dog is training his owner."

Got any good ones to add to this?