There are two kinds of fences: a physical barrier keeping you in a certain space and a mental one that nobody else can see. Both prevent you from escaping
A few weeks ago, in the pen next to the barn were three horses, old-man Squeak, big-boy Quasi, and good ol' Whip. We have five horses and reliable Woody and escape-artist Rooster were in stalls. From the house I can see a portion of the outdoor pen, and I look out frequently to check on the horses—the fence is not very stable.
This day in particular, I can only see Quasi, a very distinct character too tall in his withers hence earning the name Quasimodo. At this point he's pacing and looks agitated so I venture down.
To my surprise, the other two horses are gone. Part of the fence is down! I can't help but laugh because the big ol' dummy was stuck in a pen that was not fully fenced and even though he had watched his two companions leave through the hole and still, in his mind, he was stuck in there.
I couldn't even be upset. The poor guy was stuck by his own doing and old-man Squeak and good ol' Whip were content grazing far out in the pasture, a pasture that is not completely fenced. They came back eagerly at the sound of a grain bucket and I haphazardly 'mend' the fence by sticking the wooden posts back up and wrapping baling wire around them.