This is my version of something I found on the web. The text in parenthesis was the original, I've made it my own.
When you are tense, let me (teach you to relax) forget how to line up and lead out pivot.
When you are short tempered, let me (teach you to be patient) blow all my contacts.
When you are short sighted, let me (teach you to see) run off course.
When you are quick to react, let me (teach you to be thoughtful) threadle instead of 180.
When you are angry, let me (teach you to be serene) let me run around the ring and pee on the tunnel.
When you feel superior, let me (teach you to be respectful) drop the last bar of a steeplechase run where I'm the fastest dog.
When you are self absorbed, let me (teach you to think of greater things) trip you as I come out of a tunnel.
When you are arrogant, let me (teach you humility) go into a tunnel but not come out.
When you are lonely, let me (be your companion) snuggle up to you and resource guard you from all others.
When you are tired, let me (carry the load) pull on my leash.
When you feel financially secure, let me show you some vet bills.
After all, I am your dog.