Hehe, I was practicing with Crunch walking at my shoulder once and decided to get him to walk around some oil drums with me. He got carried away and walked all the way around the drum and back to my shoulder, becasue he came back to my shoulder I clicked him - then before I knew it he was walking around and around the oil drum not stopping at my shoulder just looking at me as if enquiring where his click was, trouble was I couldn't get him to stop and he went around and around for ages just looking at me more and more annoyed (expectedly) - by the time he stopped and I was able to get some behaviour that I could click without reinforcing the barrel thing again, he had walked a big groove in the sand around the barrel. Guess it was a misstimed click that set it up, but more to do with me thinking I was clicking for one behaviour when Crunch thought he was being clicked for something entirely different :}
I inadvertently taught Henry to stop upon any hand signal! The idea was to teach him to halt upon command so that I could use road junctions a bit more safely. What I was doing was moving my hand into my pocket ready for the treat, but he suddenly took this to mean the cue to halt. So, turning off the road onto bridleways or turning right at junctions became more of a hazard as he started to stand still and wait for his treat! He stopped any time I scratched my head, itched my leg, moved my arms....
Funny to remember it now, but it was so bloody frustrating at the time! You'll be glad to know that we did retrain the halt to a verbal command, from the ground!
I managed to teach a horse to stand only when I walked backwards around her, she had sweet itch and putting on her Boett rug became an art form!
I meant to teach stand while I walk away from you, but to make sure she was ok and not off attacking other horses (Unbeleivable space issues, poor mare) I ended up walking bakwards so I could keep an eye on her....
I used to spend hours walking backwards in circles around the poor mare trying to get close enough to put her rug on. Bless.......